Trying to build New City

Ok i am at 7k prestige and at a knight level. I have a Town hall at Level 5. Why can't i Build a new city? There is a flat by me. When i put the curser over it, it say "Lvl 1 Flat - Build city avaliable" when i click on it all i can do is attack it or scout it. Is that what i want to do? Everyone just keep saying conquer it. how do i do that. By attacking it? Thanks

On the main page, in the column under the picture of your city you will see a picture of a fortified town or castle(if you like). Hold your cursor over it an you will get an explination of what you need to establish another city. You have to occupy the flat first. Once you have occupied the flat, now when you click on the spot you should have the option to build city.

You only need Baronet for your third city.
Look at the little symbol in the bottom right hand corner next to the chat box. Hover your mouse over that, and it will tell you what you need.