b2cb The maps from OpenSupermaps.com are in obf format and when you download them to your phone, they should automatically open up and import into OSMAnd+.
Note that the maps are large. And you will need the larger overlay maps before you can download individual state maps for everything to work properly. Simply go to the left-hand side of the app's "Download Maps" tab and download the requisite world and country overlay maps. Then the individual maps from OpenSuperMaps will have the embedded street addresses so they are easily searchable in OSMAnd+~.
There are also quite a few navigation settings for driving and using OSMAnd+~. f you want TTS prompts while you're driving from OSMAnd+~, you will have to download a separate app called RHVoice from F-Droid and configure it to your liking.