Not sure whether it is the actual flying part that you're nervous about or the check in procedure, transfer etc. that you are nervous about.
Don't worry about the flight you'll be fine.....As for check in etc.... Know your flight number, when you arrive at airport, go to the appropriate desk to check in. When you go to the departure lounge, listen out for announcements for your flight, but more importantly, check the screens regularly to see which is the departure gate and when boarding is for your flight. At Corfu just follow the crowd until you are through passport control. If you have transfers included there will be reps from your tour company with boards. Just go to one , give your name and they will direct you to the approprate coach. Simple as that.
Bit daunting on your first trip, but you'll soon get used to it. Good luck and enjoy.
Oh! Just thought, in all the excitement, don't forget to collect your luggage.
S and J