Main Phase 1

In Main Phase 1, the Turn Player may: After Main Phase 1 has ended, the Turn Player may choose to enter the Battle Phase. If he/she chooses not to, the player automatically proceeds to the End Phase (he/she may NOT enter Main Phase 2).
 * Normal Summon, Tribute Summon, or Set a monster.
 * Special Summon a monster(s).
 * Manually change the Battle Position or perform a Flip Summon a Monster Card, provided it was not Set or Summoned this turn.
 * Activate effects.
 * Activate or Set Spell and/or Trap Cards.