How to remove slow-rise blinds?

[Mikendebbie]

The slow rise black-out shade over the dining table will not stay down and I have to hook it on the bottom of the side valence to make it stay. It rolls up correctly. I emailed Irvine Shade and they wrote back that I need to remove one end of the mechanism and reinstall it so that it engages the teeth in the inside mechanism, and she referred me to the videos on their website. However she did not tell me how to remove the blind from the valence head and the videos start with the shade laying on a table.

I see 3 black metal devices that are obviously the key to removal but I fiddled with them and yielded no movement. I’m sure it will be something very simple.
Anybody know how the release works.