This is another very easy achievement. It is unmissable!
On the world map, press
to enter the menu. In the menu you find one symbol that says "guild". push
and a new screen pops up that ask you if you want to join a guild or create a new one.
If you create a new one, you have to pay 1000 gold pieces. The achievement unlocks for both options. Just select whatever you find more suitable for you.
Hope this helps!
Any improvements? Please let me know in the comments below!