At Lhasa airport, there is a different terminal for domestic and international flights.
If you are taking flights from other cities of China to Lhasa, when you arrive at Lhasa airport, you can follow the domestic passengers out of the airport. The main exit you will find the officer checking for your Tibet travel permit.
As you exit the main building of the airport, you will find a lot of buses right near the gate. Those are the shuttle Bus parked at its station. You will have to come directly to the waiting area on the main road to see your tour guide ( Refer to the image on the left). Please do not wait for your tour guide in the airport building.
As you are present, the white scarf - Khata ( for the welcome ceremony). You will have hand over the original Tibet Travel permit to your guide. The journey from Lhasa Airport to the Main Lhasa city is about 60 Kilometers and would take about an hour. Please keep your passport handy on this journey.
https://itibettravel.com/tibet-travel/flight-to-tibet/shangrila-to-lhasa-flight/