Scrub a dub dub

I've acquired a new tool to scrub my kitchen floor - a vintage Sears/Kenmore shampooer/polisher. Problem is, I don't know how to use it.

There appears to be a tank that holds water and there are 2 large round scrub brushes on the bottom. My guess is that you put some kind of solution in the tank, depress a "pull up" knob near the top of the handle to release the liquid. There are 2 speeds on this thing and a "scrub" setting. If anyone's used this before, can you explain:

1) How much liquid should I put in the tank?
2) What would be the best shampooing solution I should use? I hate to buy something commercial when a mixture of lysol would do.
3) Can I just put "water only" in the tank, sprinkle some Ajax on the floor and scrub that way?

I'm ashamed to admit that my floor hasn't seen a good scrubbing in about 3 years. With the spine problems I have, I can't get on my hands and knees to scrub my linoleum well. I couldn't very well ask someone else to do it for me. I thought using one of these scrubbers would be the best solution.

I'm planning to tackle this thing tomorrow when the kids are at school. Any advice would be appreciated.