slave flashes

Hello. First post so be gentle. I picked up a couple of Morris Studio slaves for cheap. Love that they are portable. Both units are missing the sync cable and I'd like to have one just in case. Especially for some older film cameras. I thought it was a regular Household to PC, but the female...

I have a Nikon D5200 which is not a high-end camera, I know. It does not have the menu settings for channels & groups of external flashes. So in such conditions how can I use the Nikon D5200 with multiple external flashes? Say I want to create a scene with 3 or 4 flashes (a key light + main +...