On page 147 of the User's Manual, it says the following..
Press and hold down the MENU and INFO buttons for more than two seconds. "Reset completed" is displayed in the rear LCD panel.
There is also a picture in the manual of the two buttons to push and what the display looks when the reset message appears.
Haven't tried it on my F6 but that sounds like the "standard" Nikon reset procedure.
Note...you can also go to the Nikon USA website, bring up the Products pages, select Cameras, then select Film Camera, then select F6, then select SUPPORT tab on F6 page and on the right there is a link to download a PDF version of the User's Manual..
Two things I should have added in my original post...
At the bottom of page 147, it talks about resetting the Custom Setting Menu, that you should also do because that is where the previous owner is likely to have made changes for things such as AF parameters, button settings, etc. The CSM values are not reset when you use the Two-Button Reset.
The other thing that sometimes catches new F6 users is setting the "Recording Shooting Data". Those values can ONLY be changed when there is NO film in the camera. The manual mentions that but it apparently gets overlooked often times.
I normally use a Nikon D3 for sports photography but I still enjoy getting the F6 out and running a role of film thru it. It often takes several weeks before I complete the roll plus another few days to get it developed (there is no local source and I can't develop it myself), but I still get the "old time feeling" of excitement to pull the prints out of the envelope and look at them versus just looking at a computer screen. My last roll mostly contained old rusty cars, I shot them with Kodak BW400CN.
You basically sandwich the film between a sheet of glass and mylar (or acetate) using scanning fluid, which is optical transparent. You generally get the best scan you can get, due to the reduced scattering of light.