So either I'm stupid or I'm blind

I've crafted soul lanterns and caught monsters,

now i have to build the monster hall and big farm.

so far i have understood everything, but i can't find the npc in the castle for building the constructions

Sir Edward in your throne room brings you to the overview map, on which you can fight with your vanguards and construct different buildings for your country.

ok thx i missed him by searching xD