Used camera with no manual. cannot und...

My condolences on your loss. I hope you have fond memories of him every time you use the camera. The owner's manual can be downloaded at http://ca.konicaminolta.com/support/manuals/film-cameras/film_mf_slr/xg_7/xg_7_manual.pdf  It takes S-76 silver batteries which are pretty easy to find. Check Radio Shack or a similar store. You can use any MD mount lenses. Minolta's lens brand is Rokkor, but you may find others with a compatible mount too. Film loading, advance & rewind are manual. So is film speed setting. There's a semi-auto exposure mode "A" to help simplify shooting while you learn the rest. The manual is pretty good & has lots of pics of the various dials. Much easier reading than many current ones. Get a few rolls of cheap film & have fun!