Imagine I’ve just installed OsmAnd on an Android phone and want to change the rendering slightly.
For completeness, the OsmAnd version is 3.5.5, I downloaded it from Google Play, where it’s called “OsmAnd - Offline Travel Maps & Navigation”. The Android phone is a Blackberry DTEK50 (actually a badged Alcatel design) running Android 6.
I ran OsmAnd and skipped the initial download (because I’ve already got some .obf files to install), but you’ll probably want to download some local data.
I want to copy files to and from the device, so I’ll plug it into a PC. How you copy files depends on the OS on your PC. Next, plug the device in via USB and select “copy files via MTP” from the prompt that appears on the device (this actually varies by Android version, and what options are available to copy files to and from a device depend on that and the phone itself). A window showing an MTP connection to the device contents will probably appear - check you see something in there. If you don’t, unplug it and plug it in again.
I’m running Ubuntu Linux on the PC and want to copy files to and fro from the command line, so I’ll install something to allow me to do that, check that I can read something from the device, and unmount it again:
cd
mkdir mtp
sudo apt install jmtpfs
jmtpfs ./mtp
ls ./mtp
fusermount -u ./mtp
For me the “ls” above shows ‘Internal storage’. Before copying anything used by OsmAnd in the steps below I’ll make sure that it isn’t running on the phone. How to do this varies by phone - on mine it’s “menu” and then “close”.
Next, we’ll look at what maps are currently installed. How to do this varies by Android version, but this is how things appear on this Android 6 device:
My coverage this year as per Mapillary. Since my activities spread all over the city of Berlin I tend to cross the inner city a little bit more.

