its both. put your feet into ollie position, line your shoulders up with the bolts, keep your back straight (dont hunch over the board), squat down then quickly rise up sliding your front foot up the board to the top of your bolts while sucking up your back foot to the same level as your front. Try to keep your toes on the tail when you do this & eventually youll get motion & get the habit of better centering yourself. think of it in steps like this
feet into position with your back foot slightly arched, toes ready to snap down one the tail. front foot is basically flat on the board
shoulders lined up with your bolts
straighten your back so your upper body is center with the board
squat down by bending your knees (do a REAL squat to get low dont just bend your back)
As you rise from the squat, Pop the tail while sliding your front foot up to the top of the bolts. right as you are about reach the LOWER bolts, raise your back foot (while trying to barely keep your toes on it) to the same height as your front foot. this will level it out. it should feel like one smooth motion, but if you had dissect it down to milliseconds it'd be rise-pop-slide front foot-raise back foot-land
hope that helps