Actually, you can get a free manual from
https://www.singer.com/support When you put 764 in the box for the model, there should be 3 results. The one for this machine is "W764." It really isn't a real clear manual, but it is free.
Indeed there are several youtube videos for this machines.
There are some threads regarding the White model 764 here on Quilting Board as I'm sure you have seen.
Janey - Neat people never make the exciting discoveries I do.