Waypoints can be imported using gpx of kml file format.
To import a gpx or kml file of waypoints either:
Use the instructions appropriate to the Operating System of your computer.
Re-access Atlas and open the map upon which you expect to see the route.
Note: If you previously left the app by pressing the Home button on the device, the app is held in a frozen state for re-use by double pressing the Home button and touching the app icon again in the "dock" of the device. You may need to re-start the app from a non-frozen state before the route will appear. This is a quirk of the iOS system.

We recommend that you do not import files which have more than 100 waypoints in them to the Points folder. The waypoints will be imported as “ON” so that they can be seen on the map as soon as the map is opened. The more points that are on, the more processing power has to be used and the map processing speed could be lessened. If you are going to import files containing more than 100 waypoints, import them into the Routes folder instead and turn the waypoints on or off as required.
Once the file has been copied into the Points folder
Although the copy may look like it has taken place, it sometimes takes a while for it to populate the waypoints listing. As a rough guide allow around 30 seconds for each 100 waypoints,
See section on Deleting