The Incubator needs to have growth Medium pumped into it. Once you insert your Larva, wait until it “hatches” into a new Drone. The time it takes for larvae to hatch is random. It could take 5 minutes, or it could take 30.
Now that you have your new custom Drone what’s next? You can make more of these Drones by putting the same array back into the Inoculator and Brute Mutate these Drones with Rocky Princess. This way, you will get Pristine Queens. As you can tell, this is a very long process and requires lots of waiting, power and infrastructure. This is very endgame, but very fun to mess around with.