We do not have a guide for updating the editor, but we will be releasing an updated version of PowerCMS with the new editor in it.
You could do this yourself but you would need to configure the new HTML Editor instances yourself since it won't use the values from the Globals file. Also after you replace an instance on a page you will need to make sure you set it's default value correctly. You should also check to ensure that the other server behaviors that work with that field are set correctly for the new field.
If you are unsure about performing any of these steps yourself it may be best to wait for the new updated PowerCMS.