Hello, 

 

is it possible to do this? I'm new to modding and I would like to for example create a npc, that collects some wood and build a house.

For sure it is possible to do this, and in fact it has already been done. However it is not really a simple thing to achieve, specially if you are new to modding..you may want to take a look at the MIneColonies mod, which implements npcs that literally do what you want, and start exploring the vanilla code that handles villager entities

Edited September 28, 20204 yr by Beethoven92