I bought a 135N back for my SQ-Ai via ebay. No, it didn't come with instructions. I thought I figured out how to load the insert, but when I get it all together, I can't advance the film nor will the shutter fire.

Let me run this by you guys in case I didn't load it correctly:

Open back

Remove insert

Feed film between rollers and pressure plate and fix on take up spool

Replace insert in back and close door (getting it back in is a PITA)

Yes, the darkslide is out...

Any clues as to what I'm doing wrong?