Need help creating a switch stack of 4 with FS Switches

I'm creating a stack of 4 switches using these:

https://www.fs.com/products/83325.html

I'm following this documentation here: https://img-en.fs.com/file/user_manual/s5500-48t8sp-bvss-configuration.pdf but it doesn't seem clear in a lot of places. The configuration for a 4 switch stack seems straight forward enough, but I get to this line:

Switch1_config_bvss# bvss interface # type TGigaEthernet port # group #

The explanation they give of this command doesn't help much at all:

" Configure the port port whose port type is type to be a virtualized port. The serial number is num and the port group number is group"

Funny thing too, is that the command on the documentation isn't even fully accurate. What I'd have to type on my FS switch is: "bvss interface # (1-4) slot (1-1) port (1-8) group (1-2)

I'm not entirely sure what the slot refers to, but I only have 1 option there. Port seems easy enough, just referring to the stacking port I'm using I'd assume, since there's 8 of those and I can choose from 1-8. Interface and group is where I get lost. I've tried a lot of different combinations of putting my ports in the same/different interfaces and groups but I can't seem to get all 4 switches to stack. I either get 2 to stack or none at all. Anyone with some experience here able to help?