Although many airlines allow you to check in and print your boarding pass online (if you’re not checking luggage), you can also choose to do so in person at the airport. Enter the airport in the section of your airline carrier, and locate their counter. When you get to the front desk, simply tell them your name and give them ID, and they should automatically print your boarding pass and ask about checked luggage
If you have multiple flights due to layovers, ask the attendant to print your boarding passes for all flights. Some do this automatically, but it is good to ask if they don’t
Checked luggage must typically weigh less than 50lbs and costs about $25 to start. This varies from airline to airline though, so check your specific airline's requirements online
If you don’t want to worry about checking bags, you are allowed one carry on item and one personal item - one that goes under the seat in front of you, and one stored in the overhead bins above your seat. Ask the gate attendant if your bags are small enough to bring with you as carry-ons.
If you print your boarding pass online and are not checking luggage, you can bypass stopping by the airlines counter.