It's a Kenmore, not a Singer ;- )
No need to despair, you will figure out how to use it by general advice. I looked up your model, but could not find anything right away. Play around with the machine try to identify which of the knobs controling what; stitch length, stitch width, needle position (left middle right), some machines have a good selection of stitch patterns.
This is a good general start if you need the very basics, the video is not exactly the same model, but much the same functions will be on your machine. The game is to discover the functions, even thought the knobs and levers are a bit different. For threading; place a spool of thread on the spool pin, aim for the tensioner (knob with numbered dial), look for thread guides and hooks along the way, then aim for the take-up-arm, still looking for guides and hooks along the way, then for the needle.
I'm sure a suitable manual will turn up, if not exactly your model at least cose enough to show the main functions.