For those of you who don't know, TNR stands for Trap/Neuter/Release and that's exactly the way it works. You Trap the cat; Neuter/Spay the cat and then Release the cat.
When properly implemented, a TNR program is the best and most humane solution to the cat overpopulation problem that I am aware of.
Even though the concept is straighforward and simple, the amount of time and work that has been put into insuring this program's success is quite involved and lengthy. Starting a TNR program in your area can be as basic or complex as you want.
The procedure will always be the same; it's the process that you will have to customize to suit your particular community's needs.