How do you build new buildings?

There is button in right bar 'build', after click you will see menu. Left side are categories (manufacture, housing, city building, statues, special building, wathcman building and churches. Right sides are types and levels of each type. When you choose building, you will see map with flags where you can build (or message that there is no room for choosen building). When you choose flag from map, you will be directed there. You can move freely to diferent place. When you move mouse pointer over flag, it will change in to building you have choosen. When you left click, you will place building. Building time takes 1-8 years (depends on type and grade of building). After few minutes (in game time), if you press again build, you will see that you cant place any building on place which you choosen befor. After few hours you will see that construction begun.

Thanks on both parts. I'm playing in London so on my first game by the time I was ready to build something there was only one available plot left so I saw no flags just one in the corner which I found after a while. On my second game now as an alchemist/blacksmith(so far). I found out how to collect herbs, I was missing the fact that you had to send them there from inside the shop rather then sending a cart to go buy them from somewhere, like a blacksmith has to buy raw materials. Alchemists are great, they pretty much just make product from nothing and build up to four workers at the second improvement.
Just a little stuck now, I was playing and saved one year, the next year I died but the game crashed after a few years(I had been playing for a while) now I went back to the save and whenever I try to do certain things the message "You are about to die." flashes across the bottom of the screen and I can't take that action, but now a few years have passed and I'm not dieing, is this a bug?