Before you arrive, you should get in touch with the person that's picking you up and agree on an Arrival Door (marked 1-7) on the Arrivals Level. The driver should follow signs for Arrivals, then wait in the Cell Phone Lot where they can wait for confirmation that you're ready for them at the Arrival Door — it's not permitted to wait at the Arrival Door, it's only for immediate pick-ups and drop-offs.