If you're new to ATWT, I recommend starting with Volume 2: Sprout of Untruth. Volume 1 follows three protagonists and explores their lives, struggles, and the power system in detail. I won't spoil much about it here, but if you want a deeper understanding of the world and its mechanics, it's worth reading. That said, Volume 2 and onward stand on their own, and this was where I originally planned to begin the story. While events from Volume 1 will be referenced through flashbacks or key moments, you don't need to read it to follow along.
You can always go back later if you're curious, but if you prefer to jump straight into the journey, feel free to start here.