The root ball is shaped to allow some space around the inside of the new bonsai pot. A test fit or two is necessary. The root pad is flat so the tree stands on its own, but you could use some blocks or wedges if the tree's roots aren't this well developed.
You want a space all around, somewhere around 1" or more depending on the size of the container and tree.
The container will now be prepared with drainage screen and wire. There is some information on that process in the
TreeBay Bonsai Tools & Supplies site under Azalea repotting.
