Welcome, Meg.
In addition to what you already know and bkay has told you, this machine is a what is considered a 3/4 size machine. According to
http://ismacs.net/singer_sewing_mach...s-100-199.html these machines did
not come with a case, where yours appears to have been found in a case. Also it looks like there were some 192's made in Elizabethport USA. The manual that bkay linked to evidently changed. It is now
http://ismacs.net/singer_sewing_mach...ine-manual.pdf another one can be found at via
https://www.singer.com/support which if you put 192 for the model number will link to
https://www.singer.com/sites/default...al/245_192.pdf
These machines use class 66 metal bobbins and 15x1 needles.
For getting the bobbin slide plate back on, I think the 66 manuals give better instructions. It is similar to the diagrams for the 192 but you want to hold the plate slightly raised under the presser foot and needle. Then push it to the left so that the two ends of the the spring "B" (shown on page 3 of the above manuals) fit into the groves on the underside of the plate.
The manuals also show where to oil.
Janey - Neat people never make the exciting discoveries I do.