First priority is heat. Use a reading lamp or utility light with a 100 watt bulb if you have it. Put the chicks in a cardboard box, or a plastic tote box, depending on how many. Make sure you put down paper towels first, so they can have traction. Get the light way down close to the top of the box. You want the chicks to be warm enough that they aren't all huddled under the light cheeping; that would mean they are too cold. Bring the light closer if they are doing this.
Next, get water for them. You can put some in a shallow bowl or dish and put rocks in it so they don't drown. Dip each chick's beak in the water one by one. Also, if you have corn syrup (Karo syrup) put about a 1/4 cup per gallon in the water. Only do this for a couple hours after they arrive.
Do you know how long since they left the hatchery? This will determine how long they can go okay without food. If it has been 48 hours, then you can scramble some eggs and give that to them until you can get to the store and buy some chick feed.
How many chicks have arrived?
As soon as the chicks are stable, warm, and have a source or water at least, then get to the store and get the things you need ASAP.
Good luck