Using an airport for the first time - What do I do?

I'm 16 and I've never left my home country to go abroad, but in a month I will need to fly to Germany to see my dad. Only thing is I'll be going alone and I've never even been in an airport before, so I just wondered where you're sposed to go/what you're sposed to do? All I know so far is that you go to the check-in desk first :/ If you can guide me through the steps I'd appreciate it thanks ^^