For most gardeners, blueberries are started as seedlings since it already takes a few years to start getting a berry harvest. Most nurseries and garden stores will sell them, and if your local stores don't carry blueberry seedlings there are many places online that are happy to ship.
Before you start shopping, decide what variety is best suited for your needs. Each seller may have its own selection so don't be surprised if they have more options than you are familiar with. Take the time to read labels and make comparisons. You should also examine your property to find the best location for your plants, in case that impacts which variety you need.
Choose a location that gets plenty of sun and has good soil drainage. For each seedling, you need to dig a hole deep enough to hold the plant's roots without having to do much bending or twisting of them. Plant them securely and give them a good watering to get them established. They don't have very deep roots so it shouldn't require too much of a hole.
You also have to consider the amount of space between each seedling. These bushes can get large, several feet across as well as high. Try not to crowd the plants if you can avoid it, though their branches can overlap a little bit as long as you don't need to walk between them for harvesting. A good rule of thumb is at least 3 feet between each plant, and 4 feet is even better if you have the space.
How early in the season you can plant your seedlings will somewhat depend on what variety you have chosen since some will tolerate the cold spring weather better than others. Any Northern variety of berry can be planted out when the ground has thawed enough to dig comfortably. Southern plants may need to wait until the soil warms up a little more, but you should check the instructions with your plants to be sure on that.
Once your plants are planted and watered, you should cover the soil around them with mulch. Wood shavings or straw work best. Use a thick layer and it will help keep water from evaporating from the soil. Taking the time to do this now can save you a lot of effort later when you try to keep your plants watered. The mulch will also smother out any weeds that would compete with your new seedlings.