The sciences division is a little different, check with your advisor about first draft deadllines. This is important and not something you want to put off until the last week. Some professors get completely scheduled very quickly. So if you really want someone on your orals ask soon. In general your orals board consists of your advisor, one other person from your department, one person from outside your department but within your division, and one person outside your division.
Some departments assign the interdepartmenatal members.
But you always have to find the outside the division person yourself. The next major turn in is your final rough draft. This is the draft which is used for your orals. You must have all formatting finished and abide by all library rules . Also include any graphics or appendices that you think you need.