Camps (Nomadism settlement type)

[Harkon]

I don't really understand how this works. I'm playing as the Lusitanian and conquered Brakara and the province to the east of it, both are these apparent nomad settlements, substitutes for MTW2's Castles. Is there a way to convert these to cities? Do I have to do anything specific? Do I eventually get such an option? They're incredibly useless otherwise, it seems, there's no recruitment or building options, no government options. I don't even get the new walls when they go past the Households threshold to improve the settlement.

Cheers!