This step will take care of the entire second layer!
This move is almost excactly the same as the one we used in the step before for the corners. However, we're going to be doing it twice (once each direction with a small rotation inbetween).
This move will take a piece from the bottom layer and move it into position in the top layer without offseting any other corner pieces that might already be in position.
With your T in place:
(Turn the entire cube so that the side is now facing you and repeat steps 1-4 but the other way.)