Just do it, really. Look at the airline's and airport's websites to learn about how to pack your bags and any covid restrictions (i.e. wearing a mask during the flight). Airports are usually well signed so it's difficult to get lost in them, especially smaller ones like Belfast and Cardiff. Once you get off the plane then follow around to the luggage pickup area, get your bags, then head through to the bus station and get the right bus to go to your destination.
You can also learn techniques for dealing with flying if you're a bad flyer, they're a quick google away.