[SOLVED]Setting a Dedicated Server

Convinced my brother to buy a copy of CE so we could play together. As we are mostly PVE we tough it would be a good idea to play on our own private server so we wont need to deal will some general issues people usually have on PVE servers and without the limitations of CO-OP despite being able to set up higher difficulties as we see fit for the game .

So far I’ve managed to set up the server running on my own machine and to run the game. However when I try to join the server, it says something about “unique ID”. I know that the guide says to setup servers in a different machine but I havent managed to test it out yet.

Question is. If I run the server in another computer do I will have to buy another key just for the server machine? Isnt there any way to run a server and the game in the same machine?

EDIT:Nevermind, found the answer in another post.