So, this will take you some time. Don't get ahead of yourself, this will likely come during/after the last story arc with Sigurd. You must complete each raid location and each Alliance that grants you supplies as well as the ones that increase your population. You will, after completing all raids and alliances, conveniently have just enough raw materials to build everything, so the only issue is supplies. The final addition to the cattle, grain, and fowl farms cost 1200 supplies and 90 raw materials. Loot every supply box you come across, I had to spend two hours trying to find 1000 supplies last night so to avoid that I'd say just thoroughly loot every monastery, and big cities like London and wincester will also have plenty of supplies.
I hope this helps! Good luck achievement hunting :)