Constraint Satisfaction problem

Hey, need help with this problem:

'A restaurant wants to plan four-course meal, here are all the options:

- appetizer, time for preparation 15 min

- main course 1, time for preparation 15 min

- main course 2, time for preparation 30 min

- dessert, time for preparation 30 min

In order to ensure proper service, appetizer must be prepared before main courses. Also, main course 2 and dessert can't be prepared simultaneously'

(a) As a Constraint Satisfaction problem: describe the set of variables, their domain, list the set of constraints and constraint graph.

(b) Show the search tree when applied with backtracking search without forward checking (show the domain for each variable at every point)

(c) Redo (b) but with forward checking

Any help would be much appreciated !