How to couple physics

Hi,

I've seen several tutorials in which the demonstrator is able to take the solution from one solver and use it as a constraint for the next solver.

In every case, the demonstrator already knows the expression for the output that he wants to use. For example, if I want to couple a pressure simulation to something else and need the pressure, I'd use the expression "p" because that is the one for pressure.

My problem is that I do not know the expression for all of Comsol's outputs. Is there a list that Comsol stores for such expressions?

Thanks.