(I'll explain any strange terms along the way)
Yugioh is a card game where you try to get your opponents life points, or health, down to zero, before your opponent does the same. Each player starts off with 8,000 life points. That's the basic explanation for the game.
Aaron and Crystet pulled their cards out of their deck boxes, and placed their cards onto a fold-out table that was in one of the closets. Crystet pulled out two mats, which were like large computer mouse pads, but for Yugioh, and laid them in the table.
Aaron and Crystet both placed some coloured cards into the "Extra Deck", which is where all the 'Special' monsters go. The special monsters are known as 'Fusion', 'Xyz', 'Synchro', 'Link', and the ever so confusing 'Pendulum', but we'll talk about them if they come up.
Aaron and Crystet shuffled their decks, and placed them into the 'Deck' zone, where, as its name implies, the deck lives. They flipped a coin, as Aaron called heads. It landed on tails, so Crystet got to decide who went first. He decided that he wanted Aaron to go first. They both drew four cards, as Aaron looked at thhe cards he drew. It wasn't the best hand, but he could work with it. He placed a monster in the 'Monster Zone' which was where monsters are summoned. The monster was called 'Mathematician'. It looked like an old man. Aaron activated its effect, which was very useful in his deck. It allows him to send 1 level 4 monster to the Graveyard.
What is a level? Well, it's a monsters rank! They go from 1 to 12, and when you want to summon a 5-12 star monster, you need tributes, or fodder. 5-6 stars only need 1, but 7 and up need two!
He sent a card called Shaddoll Squamata to the Graveyard, which activated one of its effects, allowing him to send one 'Shaddoll' monster from his deck to the Graveyard.
What is a Shaddoll monster? Well, it's a monster in the Shaddoll 'Archetype', or group. A bunch of cards have the term Shaddol in their name, which makes it an Archetype, and Aaron had a deck built around that set, while Crystet said he had a deck based around powerful cards called 'Sacred Beast' cards, which were their own Archetype.
Aaron sent the card 'Reeshaddoll Wendi' to the graveyard, and got to activate its effect, which allowed him to 'Special Summon' a Shaddoll monster from his deck, in face down defence position.
What is a special summon? It's when a card allows itself or another card to be brought out to the field, by activating a card effect! You can only 'normal summon' a monster once per turn, which he used on 'Mathematician'.
What is 'Defence Position'? Well, it's when a card is turned sideways! When a card is facing towards your opponent, it's in 'Attack Position', meaning that it can attack. If it's in Defence Position, but it does have a perk. If your card is in defence position, you take no battle damage!
What is battle damage? Well, when two monsters battle, you need something to decide their strength! That's why there are 'Attack/ATK Points', and 'Defence/DEF Points'. When two monsters in attack position battle, whichever has higher attack points wins, and the loser, or the card with the lower amount of ATK points is sent to the Graveyard!
What IS the Graveyard? Well, it's where cards go when you either lose them to battle or an effect sends them there!
Aaron placed a monster face down in his monster zone, and looked back at his hand. Hhe then 'Set' a card. 'Setting' a card is when you place a card in your 'Spell/Trap Card' Zone, which is where your seplls or traps go, fsce down, so you can save it for later.
"I end my turn. Your move, Crystet." Aaron said, tauntingly. He wanted to see what Crystet did, with his 'unbeatable' deck.
"Alright. I draw!" Crystet replied, drawing a card from the top of his deck, and looking at his hand.
Why didn't Aaron draw? Well, on the first turn of a Yugioh Duel, you are not allowed to draw, as you get an advantage from playing first.
Aaron didn't know what was in Crystet's hand, so he waited for Crystet to do something. Crystet placed down a 'Field Spell' called 'Fallen Paradise', which stopped Aaron from targeting four specific monsters which might appear later.
What is a field spell? Well, it's when a special type of spell gets to go in the 'Field Spell Zone'. No other cards can go there, except for field spells, and both players can activate one.
Crystet then placed a 'Continuous Spell', which means it stays on the field until negated, called 'Opening of the Spirit Gates' which allowed him to add a card which listed three names in its name or in its effect text, so, he went and took out a card called 'Dark Beckoning Beast'. He then summoned it to the field, and activated its effect, which allowed him to use the same effect as the Opening of the Spirit Gates card. He then drew one of the cards the deck was based around. One of the cards listed in the searching effect. 'Raviel, Lord of Phantasms'.
Crystet then activated the second effect of his 'Dark Beckoning Beast', which allowed him to normal summon one other 'Fiend' monster with 0 ATK and 0 DEF on his turn.
What's a Fiend monster? Well, every monster has a type, and an attribute. The types are stuff like pyro, winged-beast, fiend, and other things, while the Attributes are stuff like the elements, such as Wind, Water, Earth, Fire, Dark, Light, and then the unique 'Divine' Attribute, shared by the 'God' and Sacred Beast' monsters. He used this effect to 'tribute summon' which, when referring to the level explanation, needed a tribute, as it was a 5 star monster, but a tribute summon is still classified as a normal summon.
Crystet then also placed two cards face-down, as he ended his turn.
The game could now truly begin.