Calculating exposure times.

I'm trying to learn long exposure photography, but I'm stuck on how to calculate exposure times when using ND filters.  I currently have a B+W ND 3 which is a 10 stop reduction, I think.  My question, to anyone, is how do calculate the time eg. 1 minute, 2 minutes so on and how do you determine what f-stop, eg. f/9, f14, or f/22 when taking daytime long exposures?  Any help is greatly appreciated.