Go to Maps in Atlas on your iPhone/iPod touch and your installed map should appear under Offline Maps.
Note: If the map has been copied into the Maps folder but does not appear when you open up Atlas this may be because the app was in a "frozen" state when you copied the map in. i.e. you have previously been in the app and then hit the home button. Then, when you double click the home button, the app is sitting in the bottom bar in a frozen state - Apple's "Fast App Switching" feature. Delete the app from Fast App Switching and then re-start the app from the main window. The Map should then appear.
Touch the map icon or name and the licence code window will open up.
If you can access your licence email on your phone you may like to use the copy and paste functions on the phone to enter the licence.
If you enter manually then type exactly as shown in your licence email without the enclosing brackets.
When you have entered the licence correctly the “Done” button at the top will be highlighted in blue.
Tap the “Done” button and your map will be licenced and ready to use.