{Sylvan Library}
If I have 2 libraries in the battlefield, do I draw 5 cards?
From the card's rulings:
Spells and abilities are resolved one at a time, so if you use multiple Sylvan Libraries in one stack, each will resolve in sequence. You do not get to draw all the cards at once then put them all back at once.
So I'll draw 3 cards first, decide to put back 2 then draw another 2 cards, put them back?
Yes. Your normal draw step occurs, as no one gets priority in the draw step until you draw your card. Then both sylvan library triggers are placed on the stack, then (assuming your opponent has no way to interact and you dont wish to play any instants) the first one resolves and you draw 2 and choose to put 2 back or lose the life, then the second one resolves and you draw two more and then choose whether to put 2 back or pay the life. Of course you may only put back cards that were drawn that turn.
For a second I thought the question was about having two libraries as in two decks. I was like huh?