Well, I used to keep about 4 fish tanks, but was hoping that someone more acedemic than I would reply.
Anyhow, I always left a new fish tank up and running for at least 2 weeks with no fish at all - but this was not to allow the ammonia/nitrite/nitrate/bacteria cycle to start but to allow other [unwanted] chemicals in the water to break down - such as chlorine & flouride - which happens naturally over time. With regards to the beginning of the cycle, this usually starts by putting plants into the water to help break down nasties which can be done in the first 2 weeks. This has 2 benefits - first plants are relatively cheaper than fish and secondly as a by-product they begin to release nitrates that then attract bacteria. The next step is to SLOWLY introduce fish to add the nitrite/nitrate. I usually only allowed a couple of small cheap fish in case it was too early [FYI, my preferred fish was a couple of guppies as they are hardy, add a bit of colour and are relatively easy to look after].
The next stage was to add more fish - but always slowly. I know of many friends who added a lot of new fish too quickly. The nitrite/nitrate balance went haywire and they loast all their fish! The other thing to remember is the size of any fish you already have. I had a friend who added some lovely [quite large] angel fish - who ate all his lovely neons ....
Any other questions I can help with, please feel free to use the direct contact envelope!