I am in North of California, just bought a 3 years old 7 ft Black Mission fig tree. How do I transplant?

from pot to ground? It has about 50 fruits. It is small fruit, about the size of a nickle. Wondered why the fruit is small? Is this because it is in a pot? Is it the best time to plant on the ground now? Should I wait until it goes dormant? What's the best way to transplant a fig tree in a 1.5 ft pot diameter to ground? Thanks.