I don't have any information specific to your machine, but the the layout of the controls is similar to that of the White branded Deluxe Zig Zag sewing machine my mother owned. You might be able to find a similar machine's manual at some of the sites that sell them.
Is there an upper thread guide on the back of the machine? Usually the thread goes from the thread spool, through the rear upper thread guide, then through the front upper thread guide, down through the front thread tensioner disks, from right to left, through the thread tensioner spring, then underneath that l-shaped piece to the left of the front thread tensioner, then up through the take up arm, then down through a couple of more clips, then left-to-right through the needle.
Looks like your machine uses high-shank presser feet as well.
As far as cleaning, I would take the top cap of the machine off, and see how it looks, and open up the door at the needle bar/presser foot bar area, tilt the machine back and look underneath, and remove the needle throat plate and clean out under there.
The machine looks pretty clean, so it might just need some oil at various points, and you are good to go.