KDMAS headstrap wrong adapter for 5k+? (solved, adapter goes on top rather than inside)

[ziphnor]

Hi, I received my “backer box” with the KDMAS for my 5k+, however I am struggling to install it. The headstrap is too wide for the hole on top of the headset. There is an adapter included (borrowing a image from reddit): https://preview.redd.it/pmze422cdqy51.png?width=1372&format=png&auto=webp&s=9c1fa5f0fd5b123fe1302b5dc31423640e903c69

However, that adapter does not seem able to “click” into place on top of the headset. The top looks like this:

I have another 3d printed adapter that I used with the HTC vive audio (which clicks into place nicely), but the hole for the strap is still not quite wide enough. The two adapters are shown here (left is the 3d printed, on the right is the one included in the box):

Did I somehow get the wrong adapter, or am I just too stupid to install it correctly?

[ziphnor]

And of course, just after posting this I realize that it goes ON TOP OF the existing head strap opening, while my 3d printed one goes inside, hence the confusion. A manual would have been nice…

My next questions will be on the audio cables I think, that Y-adapter is too short, but I am probably just being stupid again…

[Heliosurge]

The Y cable I routed over the top of the comfort kit. But no not Stupid as there should have been instructions imho with pics.