Welcome to BYC! And to the wonderful world of chickens!
That is so exciting. I got the 15 order for layers (not ornamental layers though) and they were healthy, friendly and after a couple of years many are still laying. My extra was a Maran Rooster, which was cool until he got aggressive. His name was Sasha.
Have the brooder set up in advance. A good brooder (in my opinion, there are lots of methods that work) should be small at first and grow larger as they get stronger. There should be a small waterer that prevents drowning or catching a chill and the water can have added electrolytes for the new arrivals. The flooring should be easy to grip. Paper-towel is the best for the first few days, when chicks are learning to walk and eat. You can spread some chick crumble, scrambled or boiled eggs (cool of course) and other little, healthy treats for them to peck at. The brooder should be warm, draft proof and secure from any predators or other house-pets. For a brooder we've used cardboard boxes, home-made crates, wood propped up to form a square, plastic cabinets set on their side, and wooden desks set on their side. All worked well and could either be cleaned or thrown away.
Chicks will be stressed, cold, and possibly sufferings "shipping sickness" (weakened immune system from the stressful travel) and will need a little pampering. What I do is I take out the chicks and either put them right under the heat light first or tuck them under my shirt to warm them and comfort them. They love to hear soft, momma like clucks from you and to feel your breathing. After a few minutes of warming up I take them out one at a time and dip their beaks into the waterer so they know where it is and can hydrate. Those that start drinking right away are usually healthy, those that stumble back or seem to choke on it may need more specialized care. Those that walk around and peck at food should be good and can be left to settle in, just watch for any droppings sticking to their back end, which is very dangerous if it blocks their vent. Also watch for chicks that sleep while standing (for long periods) and seem slow, puffed up, or reluctant to eat or drink. These chicks may need to be hand warmed for a little while longer and given electrolyte and vitamin water by putting some luke warm (not hot and not cold) water in a measuring spoon such as a teaspoon or tablespoon and dip the water against the tip of their beak every few minutes, then let them rest. Don't encourage eating until they are stronger.
I offer small perches from day one, as it keeps chicks busy and is so fun to watch, but you can wait a few days. I put in small stumps, branches, sticks, bricks, and rocks and they will jump on and off of them, learn to perch, exercise their wings, play and keep busy (preventing aggression towards one another). The more time you spend talking to and holding the chicks the more they will tame. Chicks don't like to just be held, they tend to struggle or run away, they like to be snuggled under your shirt like a mother's wings, where they have freedom to move but also feel secure. They love that. They also love being given treats by hand (tend to enjoy this as they age more then as chicks) and as they get older they love going for short trips outside to forage with you. They can learn to come when called for a treat, to hop up on your lap, and if you spend enough time with them they may even enjoy being petted. Mine never learned to like to be touched, but they come running whenever they see me and come when called on most occasions.
Other fun "toys" to give to chicks as they get older are dust boxes to roll in, dirt boxes to dig in, chopped grass, dandelions or other vegetables to learn to forage on, insects to fight over (they love insects once they get over being afraid of them), taller perches, hiding place to cuddle under (they enjoy a mini table of sorts, so they can easily get in and out without feeling trapped but have something to hide underneath). They also enjoy boxes with bright colors as they will peck at the bright colors to see if it is food.
I know this was a long post, but I do hope it helps. Best of luck!
