flash and manual settings

[penlan]

I'm trying to get better with using my SB-400 flash unit but I hope someone can help me understand about using manual settings with it.
If I shoot in manual and set the f stop and shutter speed to the correct exposure surely if I then use the flash it will be over exposed ? I've read some things about the TTL system (I'm using a Nikon D80) but I don't really understand how it works. There's a lot of terminology which I have tried to understand without much success. Perhaps someone can help me a bit. Go easy, I'm no expert !
thanks
Penlan

[dang]

I'm assuming you mean if you set the camera to proper exposure as if not using a flash?
Maybe... maybe not. There's more to it than that. I'd suggest reading some articles starting here: http://strobist.blogspot.com/2007/06/lighting-102-12-position-distance.html