Welcome, Frodo! Lovely Singer 66 "Red Eye" you have there. The knob on the right front is to set your machine to reverse. Only the later 66 models had that option.
Here is a link to the manual for that machine. I suggest you go through the whole thing from cover to cover and learn as much as you can.
https://a1sewingmachine.com/manuals/66.pdf
This is a link to a basic 'how to sew' video. There are others online if you want to see more.
https://www.bing.com/videos/search?q...il&FORM=VIREHT
Have fun learning to sew with your machine.