The tips begin at a different place in each module. The advice moves along with the stages of the course.
There can be a period of uncertainty the moment you first encounter a physics or chemistry problem. It can be like staring into the void, and you don't know exactly what to do. This is natural. It doesn't mean that you're in trouble or that you have a block. Be patient and let your mind accommodate to the problem. Play with things a little while. Trust yourself and the problem will begin unfolding.