If the video is too confusing, you can read text below for more in-depth explanation.
This glitch revolves around getting neighbor stuck in Lost and Found box by luring him in with a closed bear trap. The video shows an optimal path to do so at the start of the game (though you can save time by closing bear traps with items and not getting caught)

You can do this easily by breaking a neighbors' window and hiding without being detected, then waiting until the neighbor goes away, after which the trap should be placed below the broken window. (Might not work all the time, but works 100% on a new save file).

See the video below for the optimal spot.

Lost and Found box is located in front of the neighbors' house, close to the fence. See the video example below if you have trouble finding it/

Neighbor will reopen closed bear traps, which is exactly what you need him to do. If neighbor spotted you while you were placing the bear trap in the box, he might try to reopen it after you break the chase by reaching a safe zone, however this is not very consistent.

To increase the chances of neighbor noticing the closed bear trap you can open and then close the bear trap (by either stepping into it or dropping something into it), and then retreat back to your house. If you've reached the house before getting spotted, the neighbor will always go to the bear trap to check it, and then reopen it. But even if you were spotted, neighbor is likely to notice it anyway, as long as you weren't caught before reaching your house.

After neighbor tries to reopen a bear trap (and starts the animation of doing so), he's going to get stuck in the Lost and Found box (almost every attempt).

To check whether the glitch worked you can go inside the house trough the main door. Neighbor will always be able to spot you entering the house from the spot he is in, however he will not be able to leave the box at all (Sometimes he gets entirely stuck in one of the sides of the box, sometimes he is able to walk inside the box, but not get out of it).
As long as you don't walk back into him, he should remain in the spot forever.

Hope this guide helps.

I personally hadn't had much luck with getting neighbor stuck in window spots as other guides suggest, so I tried to get neighbor stuck behind the chain link fence of another house by placing bear traps inside of the fence. I did this once, but while trying to replicate it one of the beartraps fell trough the floor of the map and respawned it in the lost and found box, which is how I found this glitch.

The only downside of this is neighbor throwing glue at you when you walk to your house and back, but personally I'd rather deal with glue rather than having to worry about accidentally walking into him inside the house.

Alright, thanks for reading, love ya, bye bye <3