Those people on that website would know, but how do you catch a stray cat? The closest I got was getting it to eat some tuna in a bowl but I farted and it dashed away.
Before catching a stray cat you should observe its ears. If one of the ears is cut it is a TNR which shouldn’t be caught unless it needs medical attention. Most stray cats live in colonies too, so you might be taking it away from it’s family! Unless you are going to make a lifelong commitment to this cat, I would leave it be. If you drop it off at a shelter it may be killed faster than it would on the street.