From highway 50, take the Mather Ave. exit and head towards the former AFB.
When the road turns to the left, veer to the right and make a right at the first stop light.
Follow the road to Shriever and turn right. It's the only large building visible (on the right) and you can see it clearly.
When you enter the parking lot, follow it around until you see double doors. That's the main entrance. If it's your first class, just tell them you're with the karate class and come on in.