To spend resources in the fortress

[PrincipeAzzurro]

Hi
With hellevator, i'm full of resources.
so, i think there Is a Need to spend these resources

For example to increase the central fortress and the knights room because I'm near level 100 of the mine

[PrincipeAzzurro]

thanks to hellevator, I am now on the edge of the warehouses in the fortress. How do you spend the resources?