Yeah I made this so I could fairly quickly drop/add new party members that are not necessarily mine.
The PartMemberOneSelect key would be set to what you your keybind is in game for Target Party 1, defaults to F2 I believe.
the SelfTarget would be set to what your Target Self key in game is set to, defaults to F1.

Your Target Slot 1 thru Target Slot 4 keys should end up being the same which is why I might just change the app to use those instead as most everyone has those already.
I am about to put a new version that fixed the error having to do with a party less then 4. Actually the issue wasn't party size, it not having all the variable keystrokes in the slots setup.