How to troubleshoot an Audi's engine not starting?

I have an Audi A4 and when I try to start the engine, it won't start. The lights and radio turn on, but the engine doesn't even attempt to turn over. What could be causing this issue and how can I fix it?

First, check your battery and make sure it has enough charge. If the battery is good, then it could be an issue with the starter or ignition switch. I would recommend taking your car to a trusted mechanic to diagnose and fix the problem.