I assume you are saying that you bought this car used, and did a 'factory reset' of some kind on the device after the purchase? If so, it has removed all of the previous owner's configuration information, and now you'll need to set it up to suit yourself.
On a Renault Carminat version TomTom, this is usually done as follows:
Use Menu/Set button to access main menu
Select "Change Preferences"
"Reset factory settings"
follow instructions from there.
If that's what you have done, then you need to start putting things back to rights.
Go to "System Settings" and start tweaking. Page 2 includes setting of home location, and selection of map (if more than one) and language.
Page 3 includes such things as "Set Units" where you determine whether you want miles or km, and whether you want 12 or 24 hour clock.
Exactly what does the screen say about "isn't configured" and are you able to touch the screen and get past that message?