Question on USCIS form and dossier

Do we wait to submit our dossier paperwork until after we have received USCIS approval or do we submit our dossier paperwork and then just submit our USCIS approval document after it is sent to us? For the most part, we have all of the dossier paperwork ready to go except having some docs notarized. Not sure if we should get that done and turn them in or wait a little bit until we get the USCIS form. (sorry can't remember the number of the form right now) Thanks! LeAnne