Once youve assembled your deck, find an opponent and play. Start by laying out 6 cards. These are your "prize" cards. One of the ways to win is to draw all of these prize cards. Then draw 7 cards. Lay any basic pokemon facedown in the active pokemon area, then place any additional basic pokemon you want from your hand into the bench area. If you dont have any basic pokemon, shuffle your hand into your deck and draw 7 cards. Your opponent can then draw another card. Flip a coin and call it for who goes first, and begin!
The order of the turn goes like this
1. Apply any affects from status conditions
2. Draw a card
3. Play as many item cards and basic pokemon as you wish. You can only have 5 pokemon on your bench. Play up to one supporter card and up to one energy card. Evolve any eligible pokemon. In order to evolve a pokemon they must have been in play for more than one turn, and you must have the appropriate evolution card in your hand
4. Attack! Apply damage, factoring in weakness and resistance, and applying any affects of the attack. In order to use a pokemon's attack, you must have energy cards equal to or above the shown amount on the card
Attacking is always the last thing you do on your turn
If you knock an opponents pokemon out, you select one of your prize cards (without looking at it) and place it in your hand. If you draw your last prize card, you win! There are two other ways to win, and those are if your opponent has no more pokemon on his bench when his active pokemon is knocked out, or if your opponent cannot draw a card due to their deck being out of cards.
If you are truly interested in learning how to play pokemon tcg, i recommend going to the pokemon tcg homepage and playing through the tutorials they have