Can I back up more than one drive?

I have two drives on my computer I would like to back up.  I have backed up my C drive and then I went back and selected the second drive and it read it but wont give me a “start back up” option.  Am I trying to do something that can’t be done?

I think I figured it out…the “back up” and “retrieve” tabs were grayed out but I just needed to click on the the “my book” and it opened it all up … I am backing up now.  Thanks.

I have begun my backup and have several external hard drives. it is very strange because only parts of each drive are being backed up. Why is that happening? How can it be corrected? There is plenty of memory in the target drive. When i try to restart the backup it says partial backup accomplished. Remaining files will be added later. Also, can I program an automatic backup rather than manually do it? Does the backup work real time? Thank you for any help.