What to do when I get to the airport?

I am traveling by myself for the first time via airplane. I am leaving the country and I have a layover of approximately one hour each way. My question is, can anyone tell me step by step what I am supposed to do when I walk into the airport? I just don't have a single clue! You used to get a boarding pass in the mail and now I hear something about a Kiosk? I am pretty nervous about missing a step and being stranded at the airport! Please someone help! Thank you.