Haha I had this very same question last year when starting off.
(Such an innocent question that I am still wrestling with to some extent.)
If you are a noob like I was then I recommend really just messing with C3 for a couple of weeks and get familiar with with as many features as possible.
Then , for what you want to do, you need to focus on functions and, I would also say, arrays. Both of which C3 make very easy to use. You can even edit the arrays in the editor now where as previously in C2 you would have to make your own array editor. ( i spent many weeks making an editor in C2 which became 90% defunct over night once the array editor was available in C3.
Then as plinkie said, depending on what you want to achieve in your game there would be different ways to do things but for example you will need to run through a set of functions (which could be listed in events or stored in an array) which themselves generate enemies and also set out (or just identify) the way points for the patterns (which could be a set of physical hidden way point objects in a layout (or could be a set of co-ordinates stored in array. )