Hi David, I don't know any good maths resources. I just do web searches, and I find resources that are dumbed down to my level. The main things you need to know are basic vector stuff, Newton's equations of motion, vector dot products, and vector cross products. How to solve quadratics comes in handy too.
You can think of alarms as the way in which time is measured: at gives you a stream that fires at the absolute time given by the cell you passed it. The cell time is a continuously varying value giving you the current time. If you snapshot time, you can add some number of seconds (or whatever your units are) to the result, hold that, and pass it to at.
