Retrospect is a hard program to pin down when it comes to usage. On the one hand, it has a myriad of features designed to make your life easier in the long run, but which can be a tad confusing right off the bat. On the other hand, once you've got Retrospect set up or if you decide that you don't want to do complex archiving, it's terribly easy to use.
The program starts off with a window containing four buttons, Backup, Archive, Restore, and Retrieve. Since the difference between backing up and archiving, as well as restoring and retrieving, isn't all that clear, Dantz nicely explains them in that window. Backup is a plain and simple backup that copies all the changed files on your hard disk to the backup disk(s) each time so that you can always Restore the complete hard disk to the exact state that it was in before. The main purpose of Retrospect is to Archive files, but primarily selected files, to backup media, and then to Retrieve individual ones when you need them later. Dantz added the Backup and Restore capabilities to Retrospect in version 1.2 because people complained that they didn't want to do complicated archiving all the time, and while I think the Backup and Restore work well from that point of view, archiving is a much better and more flexible method of protecting your data, as I'll show later.
Backing up a hard disk is a simple process. Run Retrospect (that step should be obvious). Click the Backup button (still pretty clear here, no?). Select a Source, the hard disk that you want to back up and click Next (not getting much more difficult yet). Select an Archive, or, if none exist, create one. Selecting an Archive is easy, a matter of a click. Creating one is a tad harder, since you have to click Create New..., select the media type (there are usually two choices, Combined File, which is good for backing up onto another large hard disk, and Macintosh Disk, which is what you normally use with floppies. Any tape drives you happen to have attached will appear here as well.), name the Archive, and save it. Note that the only confusing part of this is dealing with the two main types of archives, Combined File, with which you save the Archive on the disk the Archive will be on, and Macintosh Disk, with which you save the catalog to the Archive on any volume other than the one you will be backing up to. It's slightly confusing but makes sense after a while. Once you've created and selected your Archive, click Next and watch Retrospect list all the files that it will back up in a nice hierarchy. This being the first backup, Retrospect selects all of the files, although future backups from the same disk won't duplicate files on the backup. Click Next and check the Options, which are Verification (compares the files after copying them), Compress Files (self-explanatory), and Always Full Backup (backs up all files each time). Finally, click Execute Now and watch it go. If you use floppies, be prepared to feed the disks into the drive and OK the erasure. New disks format automatically.
Restoring an entire volume is equally as easy and simply reverses most of the steps. First you select the Archive to restore from, then select the Snapshot, which is what Retrospect uses to keep track of exactly what your drive looked like before. Then select the Destination disk, and finally the files you want to restore, although the program selects all of them for you automatically. If you've backed up several times and have multiple versions of the same file (modified at different times), Retrospect automatically makes sure you only see the latest versions. Neat eh?