How to claim an abandoned dwarven fortress?

is there any official ruleset for claiming abandoned land in DnD5e? 🤔

Last session we’ve entered an abandoned dwarven fortress. My dwarven characte, a child of thunder, wants to lead the dwarfs into a new century and increase the dwarven empire.

So I think about claiming the fortress, restore and repopulate it.

Are there any rules or common ways how to do it? Or can I simply go in and say "it’s mine now".^^

If it’s important: it’s about Axeholm in Sword Coast, Faerûn.

My dwarf is an artificer but wants to get a Hammers of Moradin paladin and is a strong believer in Moradin nd it’s values.