So i saw hyuuka's post about basic knowledge and thought i'd expand upon it a lot for some of the newer members of the site or to the game in general, so for this ill just suspect whoever read's this has no prior knowledge of the game.
During each of your turns you have 6 phases which you can do certain actions in (Draw Phase, Standby Phase, Main Phase 1, Battle Phase and End Phase) main phase is mainly for setting and summoning monsters ( which you can only normal summon once per turn). Draw Phase is the beginning of your turn and you draw one card unless stated differently by a card effect, standby phase is mainly meant for certain card effects to activate.
Battle Phase you can attack ONCE (unless stated in the card effect) per each monster, and end phase is the phase where you transfer turns from yours to your opponents. So that's a continuation of hyuuka's if everyone would like i could probably continue with this.