So it got me then (in accordance with that video) made, and so it has then also works for me:
You can drag the end of the strap through the ring on the ceiling and then through the gymnastic rings, then (according to the arrow mark on the quick release of the back) by the quick-pull (quick release while pressing), then the protruding end (down) depends back and can fold it into small loops and secure it with the Velcro on the belt. But the best view the video "How to Hang Gymnastic Rings" ;-)
The rings are now holding, the belt does not take place at the quick-apart (this happened namely when I tried to pull the strap only by the gymnastic rings and then immediately through the quick release).
By better functioning method above all is thus "a single large loop".
On the ceiling (concrete floor) I have concrete anchors M10 used and screwed a ring nut on. In the ring the ring nut a carbine was hooked, so that the belt is not in the ring of the ring nut always scrubs directly. The belt then I have described above through the carabiner and pulled through the gymnastic rings and then closed with the quick release.
As far as my experience in flying rings mounting :-) Good luck.