On ismacs there's a
generic manual for the 15 clones, it will work for your machine.
This one looks pretty close to yours. There are slight variations on them, and when you clean and oil the machine an intuitive approach is the best; all moving parts where metal touches metal needs oil. Take out the bobbin case, bobbin cover, face plate and round lid in the back, there's losts of oil points there. Have the stitch length lever on maximum; turn the hand wheel and you will easily find the oil points by observing the moving parts; hinges, joints, end of rods, and the back side of the stitch length lever. Both the presser bar and needle bar needs oil.