I am confused about the multisession feature. I have a gigantic office application that I need to back-up (8 Gig's). Is there a feature to back up data with a multi-disk setting. (eg. one 4.7 Gig disk is filled, then the software prompts you to insert a second disk to complete the backup.) Thank you in advance for ideas.

no.
multisession just means that the program will leave the media 'open' if the data you have written does not fill the disc completely.
'open' means, that you can add files later in a 2nd burn-'session' - up to 99 sessions are allowed.
e.g. you burn only 10 mb on a CD, it would maybe be waste of media if you close the disc that you cannot write on it anymore.
if you burn it multisession, you could later add new files to the disc, because the disc is not 'closed'.