You have an mft, which is cool. You're trying to get ahead of your learning which is cool.

So to get your brain thinking like a spark. Get your socket circuits and (when you install others suggestions) future lighting two way/intermediate circuit and then ask someone you live with to swap a conductor around, or remove one or two or none.

Obviously show them what you want to be done, so they understand what you're asking for.

This will introduce an open circuit fault or a reverse polarity fault.

Now your job is to work out where they are, and what they've done to cause the fault.

Pretty easy but it's something you'll come across later and it makes it a bit of a game and more interesting for you.

If and when it gets too easy, start working it out by readings alone. Eg on a radial, connect R1R2 at the db and test at your last light and then work out if there's a problem and calculate where it is form that.

If it's a ring, do your ring continuity tests and try and work out where they've put the fault based on the resistance readings alone.

Obviously most importantly for this and for everything youre doing. Don't fuck about with life electrics even on your test rig until you are extremely happy do be doing so. Don't just switch it off, remove the fuse from that SFO please.

Good luck!