Shower drain washers.

I finally have the insulation behind the shower and I am putting the one piece fiberglass shower in. I bought an Oatey drain a couple of years ago when I was installing the dwv system and I can't find the instructions.

Which washer goes on the finished side of the shower and which one goes underneath on the unfinished side? It has two washers. one is a thick black rubber one. The other is a thinner red and white one.

Thanks in advance.

washers

The all go on the unfinished side. Plumber's putty or silicone goes between the drain and the finished side.