New event: Hold your mouse down and drag
Move event: Hold your mouse down at the top of an event and drag
Resize event: Hold your mouse down at the bottom of an event and drag
Edit event: Either double click on event, or hold your mouse down at the middle of an event and wait until a textarea appears. Click outside of the textarea when you're finished or hit the escape key to cancel the changes
Delete event: Click on event and press delete key on your keyboard