How do you go about getting a cubic zirconia put into your engagement ring?

My engagement ring got stolen so now we're back to looking for a new one. My fiance had spent quite a bit on the diamond so I convinced him to let me put a cubic zirconia in this new one for the first year and replace it for our first anniversary. I'm not entirely sure where to go to have one put into the band I'm having designed though. I probably sound pretty stupid but can anyone tell me how this works?