A: You can choose to take any or all of your Draws from the bottom of the discard pile, and you can do it in any order. You can take one off the draw pile, then one off the bottom of the discard pile, then one off the draw pile, then one off the bottom of the discard pile. Each time you draw, you can choose which place to draw from.
Since you can look through the discard pile at any time (without changing the order) you can look at all the cards near the bottom of the deck, and see if drawing four cards will get you to a specific card you’re looking for. It’s a pretty powerful promo in some ways.