You have to work the problem backwards.
1) the two blocks go v = d/t with no friction and constant v (Given d and t)
2)There is conservation of momentum so m1v1 = (m1 + m2)v12 (You know m's and v12 from problem 1 solve for v1 - answer #1)
3) Assuming constant acceleration you know that 2ad = v12 d = h/sinθ from the geometry and you know v1 - solve for a = answer #2)
4) I don't know if you are doing energy yet, here are 2 ways:
Energy mgh - Ffd = 1/2 m v12 Energy initial - friction work = final energy (all kinetic) You can solve for the force of friction
Then the coefficient is solved for using Ff = μmgcosθ
or Forces: mgsinθ - mgμcosθ = ma The m cancels and you know everything but mu.
Please consider a tutor.