Your first draft is just that – a first draft. Everyone always has to revise it so don’t be surprised that you will need to as well. Revisions often need to be whole scale structural rearrangement. In this post Pat Thomson talks about a method for doing this by physically cutting your work up with scissors. You can also do similar things electronically using the navigation pane as I have explained before in my post on Rearranging sections of work in Word.