Allen,
No such thing as a dumb question. This is what I think I know!
Voltage reading vs percent charged.
12.6v 100%
12.4v 75%
12.2v 50%
12.0v 25%
If your meter reads around 12.5v your golden, as Brendan would say..With the truck running, you might see as high as 14.3. This is true with an alternator, but I don't know if the GEN will do the same thing.
Your meter is telling you the "pressure", or voltage in the entire system. Did you read the manual? Bad boy!
Stuart