how do i make two faces align with each other?

[maiden bone]

i'm trying to recreate the roblox studio dragging system where it connects the closest face of the dragged part to another part.
i have the look vector of the closest face but i dont really know what to do with it.

all the other dragging systems i found either used the dragger instance or just uses the bottom face to connect them both
in this case i want it to be dynamic and i dont really know how to get the other look vectors from just one

I want it to work like this, does anyone know the math for it?

[golden pond]

Hmm maybe try using the align orientation thingy

[dense stirrup]

Ask the wall what side it is