How difficult is changing the starter n a 2001 Isuzu Trooper?

not a mechanic (can change oil, battery). I believe the starter solenoid is bad but I have no way of testing it other than to take out the starter to be tested. The battery is good (tested) and I changed the relay (hoping for a cheap fix). I hear a loud click when I turn the key, but the starter does not give me the multiple clicking sounds.