It's best to complete all the "skills and drills voxL < getting started and learning to program" badges first. (To get to the badge tutorials click the blue square on the homepage). These will show you the tips and tricks for working with Blockly and some core coding concepts. The game events section in the "learning to program" section will introduce player interact events, among other events.
Then after that, you might be interested in the sidekick badge tutorials.