First of all you’ve got to keep in mind that extenders are supposed to be worn for severals hours a day. The feeling should not be the same as manual stretching, you should hardly feel it at all.
The basic function is to keep the penis in an elongated state for a long time, and you do that by setting the appropriate amount of bars on the device and then strapping it on.
I would recommend first setting the fine tune to the lowest setting possible.
(Rhere are 2 fine tune parts on the SG, one can be adjusted by holding the wheel at the base and turning the rods, the other by holding the rods and turning the wheel, a thinner rod with screws on it should appear on the base of the device and on the base of the first rod, but don’t unscrew them too much or they will come off).
After they are at the shortest mode simply put the extender on and you can slowly increase tension by inreasing the length with these fine tuners.