Setting up part sense with GIII pendant TM1800

I'm writing a program where there are multiple stations and I want to use the touch sense to sense if the part is in the station or not and if it is then have the robot weld the component and if it is not to just move onto the next station and continue doing the same part sense. I have the top of my program to GET-TSF and It will do the part sense how I want with the -Z axis, but at this point I am confused on what to do with the IF THEN statement. Any help will be appreciated, thank you!