Clan hall are about to be released, there a few things still need to be sorted out to make it can be configured by system automatically; like adding npc, portal, hidden entrance and etc
If you want to have a custom clan hall map you can design yourself using the map editor here https://enexiatk.com/MithiaMapEditor.rar map size must be exact 30x30 tiles
Here is the default hall sample, if you make changes make sure to edit the F3 path also to mark walkable part https://enexiatk.com/default_hall.map