I believe you just stay airside & keep walking the corridors heading towards T1. It's a bit of a hike, but not horribly so. I'm really going from memory here but when you go towards T2 & T1, if you come to the big center section where folk might be checking in, always stay on the back (airside of it) & then there are hallways between the 2 terminals. As you cross the hallway from T2 to T1 just before you get to the main section, keep your eye out for T1 & make a hard left just before you enter T1.

There will be a short corridor that will plot you into airside T1, and then you either go to the B RCC which is quite close if people are meeting there, or start walking down the B concourse to the middle where it says C concourse, and take escalator down to the underground tunnel. When getting off the escalator at the top turn left & C RCC is across from Gate 17.

Cheers.