Elasticsearch ICU_plugin for Unicode accent-insensitive search

I have been asked to share this with the community. These are my notes for using the ICU_plugin with Elasticsearch on Xenforo. In this, I create a separate "field" so that the normal XF index is left alone and this is added. It makes it easy for me to change from one to the other.

I am no expert. If anybody knows better, please comment. Also...