There are many resources that you can try to gain familiarity with the software.
Firstly are the numerous examples and templates that come built-in.
Then try the Tutorials section. If you follow the following Platformer Tutorial you should gain an understanding of many aspects of the software.
Finally, try and build something - easy at first - of your own design. If you get stuck, just ask for help. There are many users willing to try and help if they are able.
The 'How Do I' section is the best place to post if you get stuck at any time.