I think you have everything you need. These machines are held by a hinge pin. From the second photo I can see the hinges attached to the table behind the machine. When you take the machine out, there should be a short peg that swings from that. On the third photo, you can see the grub screw at the lower left. Loosen that and there is a hole the peg from the hinge will go into on each end of the machine.
Slide the pegs into the holes and then tighten the grub screw to hold in place. It is not as easy as it sounds with these heavy machines so if you have a pair of helping hands it does make it a bit easier, at least I think it would but cannot get my kitties to help me out with this.