The software allows you to download maps for offline use - just like Google Maps so you don’t need a wi-fi connection as it uses GPS. Alternatively just print the route out - it’s fairly straightforward. Basel - Strasbourg - Metz - Reims - Calais and they’re all sign posted well in advance. Enjoy!
I actually ended up using google maps today, as I was on the go already and it was taking too much time to try and download the TomTom maps. Google maps was pretty good, but it is really missing detailed junction information, I really like a visual of which lane I should be getting into at tricky junctions.