The menu item "Route" opens up an administration page for all routes. If you have already entered some routes, these are listed under "My routes". Clicking on the route names or "View route" brings you to the route overview.
The symbol "Download route as GPX file" opens up a pop-up window. Go to "Save file" and confirm with "OK". Your file with the GPX data is then saved under Downloads. You can use a data storage device (usually a SD card or USB stick) supported by your navigation tool to transfer this file to your navigation tool.