Have you done any reading about the nitrogen cycle, you need to understand this in order to understand your aquarium and maintain a suitable environment for your fish to thrive in. You dont give much info at all on your tank? I assume its not established as you are receiving ammonia readings, are you in a fishless cycle or fish-in cycle? What are your parameters; Ammonia, Nitrite, Nitrate, PH...what is it now and what do you want to raise it to and for what fish? How big is your tank etc?
But defore anyone can answer in detail you really need to elaborate on your setup and the things mentioned above.