Be ready for a lot of nail biting from the moment they ship until you get the call that they are at your post office. Do not be surprised if you lose some chicks in shipping. If it is especially cold in shipping you may lose quite a few. With luck they will get to you quickly, did you use a close hatchery or one that is further away from you? It took my chicks 3 days to get to me last February and I only lost one. Other people have had better luck, some much worse. Winter is a hard time for shipping chicks due to the cold, mid summer is bad because of the heat, people have the best luck shipping chicks in mid-spring and early fall so you can keep that in mind for the next time you might order chicks.
Make sure your brooder is up and running at optimal temp for when your chicks arrive, you want to get them into the heat as soon as possible. There are lots of threads on setting up and maintaining your brooder. Each one will have to have their beak dipped in the water and the food as you put them into the brooder box. Adding a small amount of molasses to the water will help give them extra energy and prevent pasty butt issues. Mix in just enough to make the water look like weak tea.
Check every chick for pasty butt on a regular basis. Pasty butt is caused by stress and is a form of constipation. Sometimes it's an obvious chunk on the back end but sometimes it's a small enough bit of poop to only feel when you run your finger over their hind end. If they are pasting (getting poop stuck) you will need to remove it right away, and gently, with a warm wet cloth or under very warm running water for really stubborn blockages (try not to get the chick very wet!). Make sure the chick is fully dry when you let it go back into the brooder. Pasty butt can happen again and again for several days so be sure to check often. If a butt is left pasty it can kill the chick pretty quickly. When you remove the poop it will sometimes take fluff with it. That is OK, the feathers will grow in normally later, they just look funny with the bare butts. If the temp is good in your brooder the bare butt will not adversely affect them.
Finally be ready for a lot of cuteness, constant little peeps and trills, lots of dust (if they are a living area especially), and a lot of poop! Be ready for your chicks to love you sometimes and be terrified of you others. You may even start to think sometimes that your chicks hate you, but it is temporary! Just wait until you can start introducing them to food bribes, I mean treats, and in the spring, the great outdoors!