Submariner 1680 bezel comes off

[Rhialto]

Hi, i am new here an have a 1680 bezel question.
The bezel insert just fell out yesterday. try to put it back in, but still fell out again. But even worse, i can easily put the bezel ring off, with just a push of my thumb!

I have seen online video instruction to replace the bezel, but they needed a knife or something thn and sharp to pry the bezel off...

I have read something about a tension ring, and th bezel to click on that? But i can't seem to get it on properly, i can easily push the entire bezel off again.

Hope to hear from you guys
Thanks