Very easy now that the connector is open.

Head toward baggage claim. When you reach gate 41 (should be on your left) and security is directly in front of you, bear left and follow the signs for TBIT. Follow the corridor and escalators and moving walkways, and you'll be deposited into the upper level of TBIT and enter the terminal right next to the QF F lounge.

No security reclearance, no queuing, 10 mins walk max if you come into gate 48A/B. If you come into 40 or 41, less than 5 mins.