w124 Sunroof seal replacement ???

[87tdwagen]

Hi all,
Decided to finally replace the original sunroof seal on my 300TD as it occasionally leaks water in a heavy rain and is nearly 27 years old... time to change.

The question is How To? Anyone done this and can share their tips?

I have a MB replacement seal in hand, I understand the orientation of the seal front/rear and multi-barb side up... but how is it installed and held in place? just pressure?

I read the ROM Procedure 77-130, but that has left me with more questions than answers. It starts off with open sunroof, remove gasket, then a bunch of detail regarding holding rail removal replacement, wind deflector etc, and then ends it with insert gasket into holding rails????

OK so what I gather is remove gasket by pulling straight out, orient new gasket correctly and insert into holding rails. Is that it? Is it that simple?
Any tips to be aware of?

TIA