You need to give us more information. What airports? Did you book the ticket through one airline? Normally, you go to the airline's website 24 hours before your flight, put in your confirmation number, and it will give you an option to print your boarding passes. Or you can get them at the airport- many airlines have kiosks where you swipe a credit card or your passport, it finds your reservation and you can print your boarding passes. There are usually airline employees there to help you. You go to the desk to check your luggage- show your boarding pass and your passport. They'll check your bags to your final destination. If you have a connection in a US city, you get off the plane, look at the overhead screens to find the gate for your next flight and go there. You may need to ride a train to another terminal. If you go through Chicago, it's more complicate because they're renovating their train, so you have to leave the terminal, ride a bus to the international terminal, and go through security again. At most airports you won't do that. When you arrive in the other country, follow all the other people. There will be signs directing you to immigration. Stand in line and show your passport. Go through to the luggage carousels, find your bag, and walk it through the door labeled Nothing to Declare. If you're in Mexico. there will be a post with a button to push. If it lights up green, you go through. If it lights red, you take you bag to the table on the side, and they look through it. It's random. Then walk out and find a taxi or whatever.