You would plant in a container the same way you would do in the ground, with the top of the rootball (showing the root flare) at soil level or slightly above. If you intend to grow in a container long term, then you want a high quality, bark based potting soil....something like the 5-1-1 mix described at length in the Container Gardening forum. And you will need to fertilize. You can use a controlled release fertilizer like Osmocote that will last the entire season or you can use a water soluble or liquid fertilizer every couple of weeks.

And if the plant is not fully hardy for your zone, you will need to figure out what to do with it over winter to provide cold protection.

Oops I forgot to mention that I’m in Zone 10, San Diego. So it should be hardy here. Is it a mistake to put it in a container? I was going to put it in a container that was 16” in diameter and about 13” deep.