Step 1: Find a suitable coffee plant
There are plenty of online nurseries that sell coffee trees and you should look for the species Coffea arabica which produces the bean we are most familiar with in North America.
Be patient with your tree and take good care of it. It needs to mature before it will flower and fruit and this could take a few years. It will take a couple months after the flowers fall off for the fruit (beans) to start growing.
Step 2: Pick the beans and husk the shell
The coffee bean itself is in the middle of the "cherry", and the fruit needs to be husked in order to get the bean out. I soaked them in water for a while to loosen the husk, but that really wasn't necessary because they were for the most part ripe.
It took me about an hour and a half to shuck them all, resulting in about 1/2 lb. of beans.