Newbie needs help with installed softener

I moved into a house a while back and the previous owners told me there was a "water softening system" and "it does everything on its own". After living here for a while we notice a lot more hard water stains in the diswasher, shower, toilets etc.

The only parts to this system I can find are a 4-5 foot tall x 6-8" diameter stainless steel tank topped with a control control box. The box had two dials (function/time and capacity) it doesn't have any markings as far as model number, but it looks like it might be a fleck.

The pipes running to this tank have a push valve that says "bypass" or "push for soft water". If I push for soft water the water pressure in the house drops to nill.

I can send pictures to anyone who could possibily help me understand how the system works. Also, does it really take care of itself or do I need to add salt, filter etc.? It does backwash every once in a while all over our driveway.

I've never had softener before and am afraid if I call a tech out without a basic knowledge I'll run the possibility of getting overcharged.

Thanks!
Mike