I’ve have a couple of swarm boxes that I was given 10 years ago and I’ve never stopped using them. Mostly I use them for transporting bees, but I also load them up with old drone comb and other frames and use them to actually catch bees. Here’s a really short video that explains how I do it in a manner that I’m sure many hard line beekeepers would not agree with.
When honey bees swarm, like they do most of the time when they leave their hive, they fly towards the sun — which is south on my part of the planet. The swarm cluster seems to land somewhere in a tree within 100 feet or 30 metres of their hive. Most of my swarms seem to land exactly 15 metres away for some reason, in the direction of the sun. (I consider swarming a failure on my part as a beekeeper. Good beekeeping is attentive beekeeping. Every single swarm I’ve had was the result of my inattention.)
Scout bees will look for a new place to live before and after the swarm takes place. Supposedly honey bees prefer to live high up in a tree, but if all they can find is a nice empty hive a few feet off the ground, they’ll use it. I’m pretty sure an old nuc box provides more shelter than the branch of a tree. Beggars can’t be choosers.
I leave a 6-frame nuc box about a 100 feet from my hives a few feet off the ground in a sheltered area that gets some sun but not direct sun. Here’s a video from my How to Use a Swarm Box post that shows what it looks like when a swarm has actually moved in: