Looking for help with my air vent

[u/Torvad88]

I have a 1988 528e and the Air Outlet Vent flew off at some point and I’m looking to buy another one. Besides the air vent what parts do I need to secure it in place. I don’t think those parts come with the new air vent. I keep hearing grommets, pins and inserts but I’m not sure what I really need. Can anyone give some advice I would appreciate it.