To access the My Maps screen, please see Working with the My Maps screen.
Sync requires an internet connection. When you click on Sync, OMN will talk to Anquet Cloud to check that all of your maps are listed. If you have just purchased a new map via our webshop, it won’t yet be listed. Simply tap on Sync, and it will update your device. Sync doesn’t download any mapping, but just updates the list of maps in the My Maps window.
You should therefore only need to use Sync after you have purchased new mapping.