For the top I totally agree with what has been said but I think we need to start on the roots first. For zone 7 it is early enough in the season to do it.
1. Pull the tree out of the nursery pot. Sort out the roots and prune them until you have a relatively flat root ball that is about 2.5 to 3” high and about 10-12” in diameter.
2. Plant it in an oil pan using potting soil with just 1” of soil in the bottom. Put a few small holes in the pan and use copper or aluminum wire through those holes to hold the tree down securely.
3. Put enough soil on top to cover the roots completely. Use a chopstick to push the soil into all the void of the root ball.
4. Put the tree in shade and water it well every day for 3 weeks until the tree recover. Then gradually bring the tree to more sunlight.
This will set the foundation for your BC to become a bonsai. Next year do everything said in previous posts to create the top. Once you have the nebari and root flare developed you can see a full picture of what you need to do at the too.