Thanks for the photos - All of them LOL! Sorry you're having such issues with posting pics. I don't see any text or ads but I have "Ad block", that takes care of such annoyances. (It's a free add-on.)
So, the lever is the stitch length regulator.
If you want, go ahead and oil the machine, that is what most of the holes are meant for. Once you take a look at the underside of the machine, you'll see at least one bar going across from the back to the needle area - anything that moves needs to have oil. If there is black, hard stuff at those joints, use a good amount of Tri-flow to loosen it up - the hard stuff is old, dried up oil.
The silver disc in the back lets you access the innards, and there too are joints that need oil, as does what's behind the front plate; I'd assume it'll be a 15 to 20 min job if you are thorough and don't encounter major stuck parts.
Enjoy your machine! It'll soon smile at you :-)