how does 97 s90 dome light assembly snap back on?

[overtcm]

I replaced the dome light assembly in my 1997 Volvo s90 but I can't figure out how it snaps back up in, without breaking the tabs while trying. I don't see what the back tabs are supposed to catch on. The old one had a broken tab and was hanging down so I couldn't see how it was before it broke.

I've searched for a video but it looks like none exists. Can anyone help?
thanks!

Carol