Hello, I thought I'd give others who perhaps have more recent experience than I but as it's quiet ... It's been a couple of years' since I've done this. I queued in the normal Foreigner queue (there were signs for an exemption line but it was barriered off). At the desk you are processed as normal but then you get escorted to a holding pen next to the supervisor desk. Because my onward airport ticket wasn't to somewhere they recognised I had to wait while they phoned the airline to check. Then you get a stamp on your passport.
All in it added an extra 10mins I'd say which is well worth it though, if you go to that pen it does make you feel like you are doing a walk of shame in front of all the queuing passengers.
Of course things may be even easier now.
Have a great trip!