Not a lot of stuff here
The ./run-emu scripts run the emulator, but you need to setup it here:
Android Studio Emulator
You need to setup one with 5.4 inches screen and API level 29, but just because I hardcoded this in the script. If you setup another emulator, you need to change the script. You can run
/opt/android-sdk/emulator/emulator -list-avdsTo list all available emulators.
Anyway after the emulator setup (by far the trickiest part), just do
npm install
npm run android