Counters 7 to 10 on the left side of the terminal are reserved for other airlines, while counters 1 to 6 belong to Qatar Airways. Qatar Airways' first and business class passengers have their own check-in facility at counters 1 and 2, respectively. They can however only be accessed through an entrance across the rightmost door of the check in area, but you are also entitled to your own security and immigration counter. Otherwise, access to the transit area is from the only security check behind counters 5 and 6.
Most flights have their gates closed 20 minutes before departure. On flights using bus gates (C20-C28, D20-D24 and E20-24), boarding can commence as early as one hour before departure. Flights to the USA and Canada are usually served at Concourse C for additional security checks, which can easily take up at least 10 minutes depending on the amount of passengers. As there are no announcements except at the gate, it is up to you to head there on time. If your departing flight leaves in less than 45 minutes however, you can alert ground staff to speed up transfer formalities or ask a buggy ride to swiftly take you to your gate.
If you are the unlucky few who will be bussed to or from the aircraft, be sure to drink a lot of liquid beforehand as you will be exposed to the desert heat for at least a few minutes, which especially during midyear can be unforgiving.
Arriving passengers may, depending on the origin, be required to undergo security check*; follow the direction appointed by the airport staff. Connecting passengers can proceed to the transit area after walking along the walkway to the nearest security check and taking an escalator downward. Those heading to passport control for entry into Qatar must go to Level 2 directly after exiting the aircraft, walk all the way to the South Plaza and take an escalator directly to the ground floor. Toilets and moving walkways can be found every couple hundred meters.