It's really confusing isn't it?
I remember reading it over and over again before it finally clicked.
Here's a great sticky that Shawnie wrote on Fish Less cycling:
Four Methods of Fish Less Cycling
A basic cycle explanation:
First you add a source of
ammonia (hopefully not fish)
In a few weeks bacteria will begin to develop and you'll see the
nitrite levels rise and the ammonia levels start to drop.
After a few more weeks another type of bacteria will begin to develop and you'll see the
nitrate levels rise and the nitrite levels drop.
When you having readings of 0 on both ammonia and nitrites with some nitrates showing, your cycle is done.
Similar Aquarium Fish Forum Threads 
Hello. Just wanted to let you know I moved your thread to the "aquarium nitrogen cycle" section of the forum. 
