The best way to learn C2 is to start with the built in examples and run them and then look at the event sheets so you understand the basic event commands.
Then start replacing the sprites with your own sprites and look at the behaviors and how each behavior is used.
Once you understand a few basic behaviors and how to set up a layout and write a few events anyone can make simple games.
Play with everything in C2 and that is the fastest way to understand what the commands do. You won't break it and it can handle the abuse.
You can always bring any problems you have to the forum and lots of good people here with experience will help you along the way.