Appointment B can only start, if appointment A has already started. Appointment B can start every time after appointment A has started. For this begin to begin relation, both appointments must not start at the same time.
Appointment B can only finish, if appointment A has finished. Appointment B can finish every time after appointment A has finished. For this end to end relation, both appointments must not end at the same time.
Appointment B can only finish, if appointment A has started. Appointment B can finish every time, after appointment A has started. For this begin to end relation, appointment A and B must not end at the same time.