Some days ago I did a live stream to talk about infrastructure-as-code and ARM templates basics. The goal was to give beginners a quick introduction why infrastructure-as-code makes sense and how very basic ARM templates work.
The live stream recording is now available here > https://www.youtube.com/watch?v=E6Ukt0DxB48

I hope this gives you a good intro to the topic and helps you to start your very own journey! Watch out for more sessions!
Cheers, Marcel