We have a lot of tutorials. Check out the basic ones first, experiment with the maker you're using and perhaps play a few games (and look at their innards - a lot of the games on the site aren't locked so you can check out how people did things in their own games).
For a new user I highly recommend just picking an engine and messing with all the commands, trying them all out and seeing what they do. Familiarise yourself, then you'll start to see what you can do and expand from there.