Chat I just bought this (used, missing RAM and HDD) and feel like a fucking retard

I'm reading the directions on putting the drives. It seems like there are multiple bays, a primary bay, a secondary bay, a tertiary bay. and a front-access storage enclosure. But I can only find the primary and tertiary. I also can't find the converter for different drive sizes.

Does anyone have any experience with this or know a video of someone showing off the different drive bays?

Ty