Take some beans. I'm weighing them out, because I know no other way to live.
I'm starting with 100 grams. Spread them on your roasting pan.
The basics: you want to start roasting at a high temperature, to make the shells nice and hot. This sterilizes them, the encourages the bean to separate from the shell. Eventually, you need to decrease the heat so that the beans don't burn.
Roasting the beans seems to be much more of an art than a science, especially without a "real" roaster. You want to wait for two things - first, the beans will crack and pop. This indicates that the bean has separated and breached the shell, which will make removing the shells much easier in the next step. Second, keep an eye (a nose?) on the aroma of the roasting beans. At first, the smell will be very vinegary and acidic - when your kitchen starts smelling like brownies, that's when you know they're done!
Here's how I roasted this batch:
Five minutes at 400 degrees,
Five to ten minutes at 250 degrees.
Take them out, let them cool. Time to separate the good bits from the bad.