If you have cleared Immigration, retrieved your bags and cleared Customs, you will come out into the Arrivals Hall on level 2. You will use one of two exits: B or C. If you look up you will see a flight status board which lists, among other information, which exit a specific flight will use, based on the baggage carousel location. So you should be able to determine which exit your friends will use.

Personally, with a wait of more than 30 minutes, I would clear everything and head up to level 3 where you will find many food and beverage outlets. There is also reasonably comfortable seating on this level and it is relatively quiet, and plenty of bathrooms. I usually wait here, then head down one level ~ 30 minutes after the persons plane has landed.

Based on a dozen or so meets and greets, some with family members I have never met so would not recognize, I now choose an exit door number and level to meet people. Standing outside and facing the front of the main passenger terminal building there are ten (10) doors, labeled conveniently one through 10, left to right. These doors are on levels 1, 2 & 4. So now I just tell people I will, say, meet them at door #6 on level 4. (You can choose level 1, 2 or 4; I choose level 4 as it is usually less congested, and door 6 as it is more or less right in the middle.)