Creating the formula was like making an ultra-complex seal. Fortunately both the original creator, Tobirama Senju's and the second great contributer, Minato Namikaze's formulas were recorded in the scroll, and given that these formulas are not really unique, Dix was able to reverse-engineer them, then make one for himself. He deeply studied both formulas and was able to understand their advantages and disadvantages.
The first version which Tobirama made was unable to stay in place for a long time, because it was running on a battery so to say. Tobirama, when making the formula, opted to use a specific amount of chakra to serve as charge for the construct, and when that runs out the effects fade and the formula fails.
Minato upgraded this concept by implementing the Eight Sign Seal's chakra transforming module into the formula, which would be able to suck in the lingering chakra around itself, then use it to charge the beacon module. This gives it the ability to theoretically go for as long as there is chakra on Earth. This is why Minato's formula doesn't disappear, even if he dies.
Dix felt like, as the next user of this great technique he should advance and refine it even further, but sadly he lacked the knowledge to do so. This will be left for the future. He had a few ideas, like being able to teleport objects with the formulas on them directly to the user, but that seemed quite hard to achieve, so he had to drop it.
He spent most of the day reverse-engineering every single part of the two formulas he was given. Even though they were small, the constructs themselves were immensely complex and had multiple layers of hard to crack code. This was a worthy challenge, and he took it head on.
Because the studying took the whole day, and some of the next day too, he took a break, so he can give his best while putting the formula together. In the end the formula constructing was pushed to the third day. It was a hard process, he copied most of Minato's construct, but he still had to set it up manually so he can memorize and put it down on his own whenever he needs it. The construct was so complex though, that building it took his entire day. If he practices a bit, soon it will be way easier, and he will be able to put one down in a blink and with only a brief touch.
The next morning he practiced the formula placement, he wanted to be as proficient at it as possible, so he exercised for the most of the day with a couple of hundred clones. Practicing the formula was quite mentally taxing, so he had to take frequent brakes, that was the time he tried to comprehend the concept of the next step he is going to take. By the end of the day, after almost a hundred of 10 minute training cycles he was able to put down the formula quite fast. He didn't actually know how much chakra he had to infuse, so he decided to experiment with it when the time comes.
He thought the next step will be the hardest, but actually he just had to follow very specific instructions and use a long sequence of hand seals to teleport himself... somewhere. That was the catch in the process, he was supposed to pop up in the dimension that is most attuned to him after the proper procedures. For that reason, the scroll had little description of what he should expect. Usually these spaces are completely empty except for breathable air... which no one knows the source of and sometimes there is some surface with gravity which the user can stand on.
Also, when he studied the exact way of how he is supposed to teleport, he found the source of his unease, and understood the severity of the situation. There was an extremely important but also unstable step while getting there. When the user performs the necessary hand seals and chakra guidance, they also have to have a deep connection with their own dimension trough his chakra. This is a very specific feeling that is hard to miss, but the scroll was unable to give any explanation of what it actually is. According to the descriptions, this connection is paramount for the jutsu to work, but the exact nature or how to replicate the establishment of said connection is indescribable and is different for every individual. The time needed to establish this connection varies from person to person too. Some may find it in a matter of years, for example Minato, who was considered a genius in many fields, and most notably in the use of space-time jutsus. But some may never find it during their life.
This last line bothered Dix a bit, but he just shrugged and started the training. He was quite sure of himself, that he will be like Minato and would get access to his very own dimensions soon. For some reason he decided to see how much time he spends on this part of the jutsu, so he summoned exactly 600 clones. That meant for 10 minutes of training he would get 6000 minutes of experience. With this, if he spent roughly 15 hours, he would get a bit more than a year of experience back. With this, if he stretches himself a bit he would be able to train a year's worth every day.
So he set out to practice. He decided if he were to experience that specific feeling of connection, he would stop right away, respawn every single clone, then try to use them to enter the dimension. If he were to go himself, he would risk not coming back at all. And that is not something he was willing to do. If a clone were to enter, they could most likely disperse and return to Dix with the knowledge of what happened, how things look on the other side and after some experimenting and training, he could try to get the last stage done, with ways to recover experience without having to risk his neck.
The training looked like its on good tacks. The cycles were going as they were supposed to. Days were going by in the extreme regimen, and he started getting tired. After a week, he felt like he was supposed to reach to the conclusion by now, and had a hard time coping with his own schedule, but he didn't think of slowing down or trying something else for a second. Actually he didn't know anything else. This was his only chance.
More days passed this way. Soon another week, then one more. When four weeks of training has ended, he already had 50 years of experience under his belt. By then he was able to cast the jutsu without actually using the hand seals, he simply relied on his chakra control and the many years spent on this one practice, just like Minato did.
He kept rereading the scroll over and over, so maybe he gets some kind of hint by reading between the lines, or discovering some hidden meaning behind the descriptions. He was already at his wits end. One night in the woods his eyes got stuck on that one specific sentence. 'Some may find it in a matter of years, but some may never find it during their life'.
This despaired Dix quite a bit. He knew he can stack hundreds of years of experience extremely fast, but maybe getting this ninjutsu was simply impossible for him. Just the thought, that he had to spend centuries trying to attain something he was destined to fail at, made him want to vomit. He was actually scared, for the first time in this life. He started falling into self-doubt and belief of ineptitude. His demons started surfacing, most notably his suicidal thoughts. The belief of failure and the loss of control made him scream as he dropped on the ground. He could already feel the noose on his neck. Something that already happened once. Why would this time be different? He started hyperventilating and after a minute or so in this state he was about to lose his consciousness. He scratched all over his face, shed his own blood by simply tearing at his skin with his nails.
He has already faced this darkness before. And the last time he lost. He desperately tried to avoid the dark corners where these feeling lied in his subconscious, because he knew he wasn't good enough to fight against them. Those dark corridors were now abandoned, the shadows stepped out into the light, and turned it into the darkest of nights. Dix felt like he was drowning, as he kept sinking to the depths of the black void of his consciousness. The last time when he reached the bottom he only found enough strength in himself to step over the line, just to be set free from the infinite darkness he was stuck in.
But this time, there was something else there.