First, you need to take a "software-independent" approach at looking at this problem. Don't force them to read the Red Bean book, or try telling them about all the nifty SVN commands. Instead, you should start by trying to teach the proper workflow with version control. In a nutshell, that means:
- Update your view
- Make some changes
- Test your code
- Update again
- Solve merge conflicts, if necessary
- Commit
Note here that I'm excluding the initial check-out process, as you should be there to help them check out their initial view. The above steps is only what SCM-enabled developers should do every day (btw, you should also really emphasize that, or else people that have a fear of merge conflicts will only get worse over time).
The key to successful SCM adoption is twofold; first you need to get people used to working with the software doing normal, non-painful things (ie, update/commit). If you don't do this, then the developers will tend to avoid using SCM until you bother them about it and ask why they haven't committed any code in two weeks. Second, you need to teach people how to overcome the common painful scenarios which might cause them to loose their work.
It is indeed possible for an SCM system to destroy work, and it usually happens before anything gets committed to the repository with merge conflicts. You should simulate merge conflicts, walk them through resolving them, and then have them do the same on their own. You should explain:
- What the meaning of the .r1, .r2, .mine, and the original file will contain after a conflict
- Show how to graphically resolve the conflicts
- Now re-compile and test the software again just to make sure
- Make a backup of the .mine file, again, just to make sure
- Then commit
There are many more complex things within SCM, and this should only be explained much later after the basics are well understood. Don't even bother mentioning merging or tagging or anything like that until they have a few weeks of everyday experience under their belts. Otherwise, the complexity and additional risk will make this new tool seem even more "useless" to them.
Again, the key here is to emphasize the daily SCM workflow, in a software-neutral manner, and slowly explain the quirks of the particular SCM system as they come up. Merging is the only complicated thing that needs to be explained at first, as it is likely the only painful thing encountered on a daily basis. Everything else should be explained as it comes up.