When Your plane lands, first You will wait for Your luggage, and then You will proceed to the exit. Once Your are out of the airport, You will see Your driver holding the sign with Your name on it. The driver knows where to stand so You can easily see him.
Both airports in Montenegro, as well as the one in Dubrovnik (CRO) are small airports with one main exit, so You don’t have to worry about finding Your driver.