Security is the most stressful part of flying - you'll queue in the security area and there will be information on what needs to come out of your bag for checking. Basically all electricals need to come out and go in the plastic tray. Your liquids must be in a clear plastic bag - they give them out at the airport, but it saves time if you've already put yours in a bag - a small square ziplock bag. All liquids, pastes, creams such as lip balm, hand cream, mascara - must fit in that bag and must be in containers of less than 100ml.
The security area is often quite pressured and busy - the staff can often be stressed and in my last flying experience - incredibly rude to passengers. You don't always have to take your shoes off - ask the staff and they'll tell you what they want you to do. Jewelry, watches, belts etc need to be taken off - put them in your handbag to keep them safe and to save time when picking them up.
Your tray will go through the scanner, then you have to walk through a body scanner. Often your tray will come out of the scanner earlier than you get to it, or you may have to wait for it. Once it comes through, pick it up and take it to the repacking area to prevent you holding up the line. Then you can take your time to put everything back in your bag etc.
Once you're through, it's much more relaxing! Go and try out some perfume, get a coffee, enjoy yourself! The screens will tell you whether your flight has a gate number yet - if it doesn't, just enjoy yourself and relax. Keep an eye on the screens, they'll show when your gate is ready - then make your way there. Once you're airside (after security) you can buy a drink e.g a bottle of water to take on the flight with you if you want to.
When you take off you'll experience the aircraft speeding up along the runway, then you're up.. It might feel a bit steep for a few minutes while you're climbing. When you land, you'll feel it slowly descending, then you'll start to see that you're getting close to the ground, and it's quite gradual - but when it actually lands there's sometimes a bit of a bump. You'll need to keep your seatbelt on while the aircraft taxis to the gate, then once they announce seatbelts off you're free to stand up and get your stuff - but beware, it becomes a bit of a scrum at this stage! There's nothing wrong with just staying in your seat and taking your time, there's no need to rush.
Enjoy it!