Keurig and freshly ground coffee

I have been buying a variety if k-cups for my Keurig, since I got the machine about 4 years ago.
I have decided to try buying fresh coffee beans, and then having them ground at the store.
What grind(is that what it is called?) should I request for use in the Keuring. Should it be fine or coarse, or womething else?
Also, I do have a Capresso grinder which I use mainly for flax seeds, but I could actually use that. The Capresso is basically one grind (I think) so I'm not sure it will be the right "fine-ness" for the Keuring.
Thanks for any help/info.