Fish-in cycles are not recommended. Even when done properly a fish-in cycle can damage fish and when done incorrectly it can kill fish.
Ammonia in the water burns the fish's skin and gills. Burned gills don't take up oxygen as well as healthy gills so the fish suffer lack of oxygen.
Nitrite binds to the blood stopping oxygen binding. It does the same to fish as carbon monoxide does to us.
Even small levels of ammonia and nitrite harm fish.
The simplest way to do a fish-in cycle is to test the water every day for ammonia and nitrite and do a water change every time either of them reads more than zero. The amount of water that should be changed depends on how high the levels are, the higher the level the more water which has to be changed.
It is recommended to use just a few fish to cycle a tank as fewer fish means less ammonia and nitrite. It still means daily water changes for a few weeks though. And when the tank is finally cycled, it is only cycled for the fish in the tank at that point. When more fish are added, they make more ammonia, and there aren't enough bacteria to cope so it could well mean back to daily water changes.
To be honest, I've got better things to do than water changes every day. Fishless cycling is so much easier - just add ammonia, test the water almost every day and add more ammonia when necessary. All you need to do is get some ammonia or Dr Tim's Ammonium Chloride and we can talk you through a fishless cycle.