Little by little! Ad one element today, read a tutorial or the manual, try things.
When I make games, there's a lot of stuff I can do with simple behaviors.
A platform is not a platform anymore, when I add the rotation behavior. It becomes more dangerous and scary! Almost like a giant saw that I can put on my level.
Want to put an annoying bird on your game? Just use the SINE behavior and set it to "horizontal". Simple things like that can help you build more interesting games and levels. Don't be afraid to try them out.