Cant find diy van high top install help

I am building my second camper van “89 chevy g20” and i have a high top for it but cant seem to find any good diy install articles or vids. only have found a few vague articles and one vid of a newer style that wouldnt apply and its pretty vague also. anyone know of any ?
thanks

Greetings!

If you look at the inside of top, there might be a flange that you screw down to the roof all the way around.

The other type require ribs to be attached to.

Put butyl tape between the top and the van.

Cheers!


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