Can someone explain a Transmatic transmission to me at the lawn tractor?

My lawn tractor has something like that, but how does it work? Unfortunately I found no corresponding description or cut drawing in the net. The gearbox has 7 pre-selectable driving steps, how does the transmission work in the gearbox? Belts, chain, gears, friction roller? Can the transmission slip even under load? (I don’t mean the belts that lead to it) Does it have an oil filling? Do the things cry on faster driving steps all of them in driving mode? Tell me what you are so darned about He knows.