When you exit the plane there will be signs and airport personal showing you which way to go and immigration agents checking your paperwork to make sure you’ve filled it out properly. If all is well they will point you towards the escalator and stairs (elevators are nearby) that lead to the immigration area. There are usually more agents at the entrance showing you which line to get into.
Be sure to have passports and immigration forms ready. The agent will scan your passport, stamp it and tear off the bottom section of the immigration form(s). The part the agents hands back to you is you “Tourist Card” which you will have to give back when you leave Mexico – keep it safe! Most people fold it and put it inside their passport. If you lose it, there is an Immigration counter/office in both Terminal 2 and 3 to help you when you depart. The process of replacing a lost tourist card can take awhile so arrive at the airport in plenty of time.
Baggage claim is to your right after you pass immigration. This can be tricky at any airport as the screens are not always updated quickly and often more then one fight is using a carousel. Once you have found the correct carousel and claimed your bags, follow the signs to customs.
At the customs inspection, all your luggage including carry-ons will go through a scanner. Once you give your customs form (one per family) to the agent you’ll be asked to press a button. A green light means go on ahead and if you get the red light the agents give your bags a more thorough inspection which usually take a couple minutes.
There are bathrooms in all three areas; at the entrance to immigration, to the far right in baggage claim and and just in front of the customs agents after you are cleared.