is it a pretty standard single stage type press? die screws onto the top of the press??
i dont know if what i do is RIGHT...just what i do...
i screw my seating die on a couple full turns and put a bullet on a loaded case and work the press...if it doesnt start seating, i'll go a few more turns on the die...once i get it to start seating, i start measuring the length with my calipers...then turn the die, crank the press, measure and keep going down with the die till i get the measurement i want..then i'll lock the ring on the die inplace...
thats what ive been doing...but im about as new as they get...but it works for me...