is it easy to replace?
Yes, very easy. Just unplug the old part and plug in the new one.
You should order the Start Relay and Overload.
The overload plugs in with the start relay.
There is the chance you have a bad compressor, but you will need a ohm meter to check it.
Chance are it's just the start relay/overload that needs to be replace.
If you do by chance have a ohm meter check the compressor to make sure it's not shorted to ground.
If you have no meter, order the parts and try them.
Enter your model number in the top left search box's to find your parts.