Play with the top card of your library revealed.
You may play the top card of your library if it's a land card.
Whenever a land enters the battlefield under your control, you gain 1 life.
3/16/2018 While playing with the top card of your library revealed, if you draw multiple cards, reveal each one before you draw it. If you put multiple cards on top of your library at once, reveal only the one new top card.
3/16/2018 If the top card of your library changes while you’re casting a spell or activating an ability, you don’t reveal the new top card until you finish casting that spell or activating that ability.
3/16/2018 Courser of Kruphix doesn’t change when you can play lands. You can do so only during your main phase when you have priority and the stack is empty.
3/16/2018 Playing a land from the top of your library counts as your land play for the turn. Once you play a land during your turn, you won’t be able to play an additional land from the top of your library unless another effect (such as that of Azusa, Lost but Seeking) allows you to.