Using VacHanger is very simple though some experimentation is required to find the best position for individual user. Use the following guideline:
1) Apply Vacuum cone over the shaft.
Where you place the vacuum cone will determine how much of the head and shaft will be sucked into the cylinder.

This one is placed bit farther away from the head. Closer the vacuum ring to the head, less shaft will be inside the cylinder. The goal is to find the best position for individual user - try close and farther apart to see which is more comfortable.
2) Once vacuum ring is positioned (after few try to find the best position),
a) Place the vacuum tube on the mouth (assembled)
b) make sure pinch clamp is in open position.
c) Insert head/shaft till it stops.

3) Once head is in and vacuum ring is stucked on the cylinder opening, suck the air out via mouth till tip of the head touches the top of the cylinder.
4) Once all air is expunged, still keeping the vacuum tubing on the mouth, pull the cylinder.
5) Suck on the tubing to see if any more air will come out.
6) Close the pinch clamp
7) Detache the long vacuum tubing.
8) And you're done. Its an amazingly simple system. It may take few tries but once determined, its very easy for next time.