Once you have created an adventure or waypoint on web and saved it, it will be automatically synced across to the FATMAP app.
You will find them in the My Adventures and My Waypoints section of the app by tapping the menu button on the bottom left-hand side of the screen (see screenshots below).
Note - If you have chosen to also publish your adventure to FATMAP, the route will appear on the map. If you have chosen to keep your route private and just save it, you will only be able to see it once you have selected it from your My Adventures list.
You can access all your adventures and waypoints offline with the FATMAP Explore membership of the Offline Access subscription.