okay, so i dont need any construction material`?
No, unless you want to build the catapult or siege tower...
Read faq, really, it is not easy to take the fief, castle is even harder, and noone have taken a town yet. Population of the fief/castle/town will act as troops defending the location. It means that is the location has its maximum population (500 for fief, 4500 for castle and 20000 for town) you have to have at similar or preferably higher amount of troops to win. Plus equipment - you need equip for EVERY single ticket - i.e. if you have 1000 troops you need 1000 armor, boots, helmets, and weapon... For that you need money :-)
Area is "divided" between clans, so even if certain location is not taken yet, you may expect it to be claimed by one of the clans. Life is hard in Calradia