Setting up android phone and PC for debugging
https://docs.unrealengine.com/en-US/…ent/index.html
Several minor issues: 1, states 4.19 for example but unclear if it will work with later engines; I think this is a general issue; 2, steps 5 to 9 should be sub-steps; 3, you can’t run the adb command from a general command exe at Step 3 (or I couldn’t); 4, you have to have Android Studio installed for these things to work.
To get the adb command to work you can go to C:\Users[NAME]\AppData\Local\Android\Sdk\platform-tools then shift-right click and select powershell / command. If you type in adb devices you may get an error. Powershell advised I can override the error by typing .\adb followed by any additional commands.
Doing this got me the RSA key fingerprint on my phone and allowed me to properly connect - but I had to go to about 5 other sites to figure this out. Would be great if it can be properly updated 
Oh - and the phone absolutely has to be in PTP mode for the RSA to pop up (confirmed on several sites).