Please help. I have a minolta autopak-8 D10. I am shooting 64T. I can adjust the exposure by turning a nob either clockwise or counter clockwise. When there isn't quite enough light normally, how do I know which direction will let more light in?

If I turn it one direction, the viewfinder meter increases in F-stop. This seems like the right direction, because it is further away from the underexposure warning. However, higher number F-stops mean less light, right?

Turning the other direction sends me into the underexposure warning. I am very confused, and need help.

Thank you in advance.