Airports are large and a bit confusing if you haven't been before so get there in plenty of time, take your time and don't panic. There are lots of boards and signs to tell you where to go. Go to departures, if you have checked baggage then you need to go to the desk for your airline and line up to get it checked in - it's been years since we checked bags so I'm assuming it's still the same!
Then find security and go through, you'll need to scan your boarding pass to get in. You may or may not have to take your liquids out and have them in a clear plastic bag - we put them in one anyway even though it's not always necessary now. Often you need them in the airport on the way home anyway. You'll have to take off anything bulky and they don't like you to over load trays so it's often coat in one, bag in another and electronics and liquids in another - electronics may not have to come out either now at certain airports though. Just watch the people in front of you and listen to the people working there.
Then you go through a scanner and might get pulled for a search, it's normal if you do don't worry! If you can't find one of the trays with your stuff in it might have been pulled - we've forgotten and left a big sun cream in there a couple of times so if it doesn't come through it might have gone the other side to be checked.
Then you're in duty free and you go through to the departures hall, check the boards for your flight they'll tell you what time your flight gate will be up. Then when your gate is up you follow the signs for your gate number. Then you wait again for your flight to start boarding.
When you arrive you'll go through passport control and then need to get your bags from baggage reclaim if you have any. When you come out into arrivals there will probably be someone with a sign for your travel company (assuming that you have one and have booked transfers with them). Otherwise they should have already told you where to go to get the coach.
Have a great time!