Crossroads, how exactly do they work?

[PRT-Drunkard]

I know I need to build em on my village claim, but what exactly do I do? I build two crossroads, take a sign from the one outside my village, and drop it on the signpost inside the walls? Or will that let people travel INTO the walls? Geh. I'm confused.

[sabinati]

take the sign from outside, put it on the one inside, you now have a one way connection from inside to outside