Installing blower on Williams furnace

[Rothrock42]

I got a Williams DV22 natural gas furnace for my greenhouse. I also got the option blower unit. I can't figure out how to install it. I've searched the web and the Williams site and can't find a single picture or video of the inside of one of these things with the blower mounted.

The issue is a screw that holds part of the grating bumps up against the fan. It doesn't matter which direction the screw goes -- I tried both ways.

The metal flange at the top also seems to poke up too high for the outer casing to go back on. But I haven't tried that yet.

Has anybody else installed one of these things?