Help - how should I hang these blinds?

[cakehoover123]

I have had Roman blinds made up by a local curtain maker. They arrived with little plastic clips at the top - see pic 1 below.

They also came with some other plastic clips, which didn't really seem to fit, but which my handyman fixed to the top of the window - see pic 2 below.

But the blinds are just resting on top of the clips. They keep falling off!

Neither the handyman or I are sure how they should be mounted. What can I do to make them more secure?

Do the square sections move to clip over the hooks on the blind?

I don't think they fit together. I honestly can't figure it out at all!

Here are some more pics - first is of the blind, second and third are of the thing on the window, from above and below.

I just can't work out how the blind was ever meant to attach to the window?

Google image search suggests the things screwed to the window are "Roman Blind Spring Block Brackets for Corded H track". No idea what to do with them though!

Okay for the benefit of anyone else who's landed on this thread, I think it's like this... c