I am originally from Japan and am currently working in the U.S. with an Artist Visa. However, I would like to go to England for the study abroad from the U.S. I'd like to know where/how to start this process.

America has nothing to do with it, if you are a citizen of Japan, you would apply to study in the other country as such.

Your current travel can be explained to the school, and may be a benefit in acceptance.

Contact the institute, follow the enrollment procedures. You can use mailing address in US. Once accepted, you would need this document when you apply for student visa at British Embassy in US.

Good luck.