Instructions for creating your first level here.
I am busy doing full-time employment stuff, but if you are so inclined, grab the latest Simply Impossible Level Editor (SILE) from HERE , and play around with it.
Until I actually get around to putting instructions here for creating your first level, I suggest you watch my poor attempt at an introduction video I recorded ages ago from HERE . I apologize for the stuffed nose :( I only got the free time to do this because I was sick...