From the Centurion Lounge, you should allow yourself twenty minutes to get to a gate at the Midfield Concourse the first time. The Centurion Lounge is on the departures mezzanine level, so you will need to take an escalator down to the main departures level. The escalators near the Priority Pass Lounge are marginally closer. From there you take an elevator down to the people mover train. These elevators are located near the end of the end of the walking travelators. As you come from the main terminal near where the travelators end you will find the elevators on the left. Take an elevator down to the lowest level to get the train out to the gates in the 200s.

It's actually very easy, the only difficulty is the elevators, while in plain sight, are not especially well signed coming from the direction of the Centurion Lounge.