I Have a question about how we arrive at the probabilities for the wavefunction collapsing to some specific value for an observable. As far as I'm aware, the wavefunction is a superposition of possible states depending on the observable we try to measure. Lets say I want to measure observable A, What is the procedure for getting from the wavefunction to a set of possible outcomes with coefficients that weight the possibilities? Apologies if the question isn't well formulated. thanks in advance.