In order to run AutoBackup.sh, the only thing you have to do is set the environment variable BACKUP_DRIVE
As so, if your desired backup drive is named USB, the command you must run is export BACKUP_DRIVE=USB
To start AutoBackup.sh, you need to open it with the bash command. E.g: bash ~/Desktop/AutoBackup.sh
AutoBackup.sh will create a .zip file at the specified drive's root directory, named with the following format: Y-m-d__H-M-S.zip
The ~/Library folder is not included in the backup.