How does one set up an "archer turret" for golems?

I still have no idea what anyone is talking about.

Set up your two other accounts with a macro looping Target Nearest Nonfriendly (or grey), attack last target

Lure golems to the turrent

edit: You can also add things like Track Players or Detect Hidden to the loop in order to help prevent thieves and the like

Do they not move out of LOS when they go beside the building?

Or is this a thing you do with the door open kind of deal?

depending on the house, you would want to set them up ontop of the wall tile via ladder or w/e

And then they can shoot straight down?

correct, they can also be hit melee from the outside, and looted, but all you have to do is back up 1 tile and your out of LOS to pks or w/e.