It looks mint! Congrats on your new washer, you'll have lots of fun with it.
The automatic rinse feature allows you to place the clothes from the wash-tub into the spinner basket, after spinning out the wash water, you turn on the water at the faucet, set control to automatic rinse and let the machine take over. It will fill to a specified level, spin out the water and will continue this operation until you turn off the water and set to spin. Depending on the load in the spinner, it may take quite a few rinse 'cycles' before the detergent residue is removed. A neighbor of ours washed for a family of five with a Hoover just like this and used to wash for two cycles of the wash timer (approx. 10 minutes) and would let the auto-rinse run the whole time or until the water was clear coming from the drain hose during the spin periods. Spin the load for 3-4 min. after rinsing is done and switch the load and start all over.
I suspect this won't be a "daily driver" but it is a lot of fun to play with and certainly a great example of Hoover history. Good luck and have fun!