Just place it in the Mach3 folder, then in Mach go to view then Load Screens. You will then need to select the file type, for Turn its lset, when you have done that you will see the screenset called 30t000.lset just double click it and after a few seconds it should load.
Now your turret problem, I would say you have the Steps per Unit set wrong, you need to find out how many revs of the stepper it takes to do one rev, also the amount of microstepping your drive has if any, you can then work out how many pulses you have for one rev of the turret and then divide by 360 to get per unit.
Hood