Archbuddy is scanning the worldmap on the current continent for digsites by itself, so you just need to start it and watch how it works. It will not move to other continents as the one you where, when you start it!
If you want to dig at Kalimdor, go to Kalimdor and start the bot. If you want to dig at Outlands, got to Outlands and start the bot..
If you want to customize the bot, look into the settings..