How to repair a damaged door lock on an Audi 80?

I recently noticed that the door lock on my Audi 80 is not functioning properly, and I suspect it may be damaged. How can I repair it myself without having to take it to a mechanic?

Firstly, you need to determine the extent of the damage. If it's just a minor issue, you can try lubricating the lock with graphite powder. If that doesn't work, you may need to replace the lock cylinder or the whole assembly. It's best to consult a professional if you're not familiar with car repairs.