FileMaker Fundamentals: Accounts & Security
People do good things - and - people do bad things. If people only did good things, we'd never need security, because nobody would fear what would happen when the bad comes out.
Of course, mistakes happen as well and killing a bunch of mission critical data is something you certainly want to avoid. So, whether you're worried about the bad things people do, or the fact that people simply make mistakes, you'll need to add some security to your database.
This video covers the ins-and-outs of FileMaker's security model and how you'd go about using it. Coming in at around an hour, this is pretty comprehensive, but doesn't cover every tiny detail.
If you've never worked with FileMaker's security and everyone is simply accessing your solution with the same username and password, then this video should give you everything you need to get started. It also provides enough information to implement a pretty complex security setup.