In order to get an advanced civilazation you need to develop. Technological progress of a province is accomplished by researchers. You can assign workers to the Motte-and-Bailey Castle and later to the Stone Keep to turn them into researchers.
The technological tree is fixed to the province, in other words in each of your provinces you will have to research those technologies you need.
How to start a research ?
To accomplish progress it is necessary to do research. Once you have assign workers (up to 100) click the [Technologies] button. The Tech Tree will be displayed.
Once the research is completed, you need to activate the effects by clicking on the [Activate] button. Keep in mind that researching doesn't cost you, activating the effects does.
List with possible technologies
(Translation in progress)