The Roadmap is directly connected to your feedback posts and displays every post that has a status that is assigned to your roadmap. Check out this post to learn how to show or hide a status in your roadmap.
As soon as you change the status of a post, this post is moved to your roadmap and appears in the corresponding column.
You can move posts in your roadmap simply by drag n' drop between the different columns. The sorting within a column is done by the number of votes.