Curtain help!

[Curtainconundrum]

Trying to hang some curtains. What is this metal bit called please? I'm not sure what to do with it.

Pretty sure the metal part is an overlap arm. It means that the drawn curtains can overlap slightly without the track overlapping.
I think the rollers are part of a mechanism to close the curtains using a cord.

Definitely no cord but I think you are right about the overlap arm. Thank you! I've hooked them on now and it seems to work!