How to make path not overwrite parent path from express.

When the site is visited you are sent to /admin witch is right, but the content for /admin's index page does not show. When I then click on the FAQ page the path should be /admin/FAQ but it is replaced with /FAQ. Then when the home page is clicked the content is shown but it looks like it is on / and not the index of /admin. How do I make it so that everything is under /admin and doesn't overwrite that part of the path.