How do I weld an unanchored model to another model when it gets a certain distance to it?

I don't know too much about welds, but how do I make it so if an unanchored model gets close to another model ingame, it welds itself to the other model? For example, if I have a magnet or claw touch a moving object that's unanchored it picks it up? Thanks!

IM not sure but ill try

here is a model: https://web.roblox.com/library/3331996487/magnet

You can use that scripts