Alternatively use esperanto.keylayout to allow Mac computers to type Eo special characters using the single option key method.
In this method option-c types ĉ, option-shift-c types Ĉ. Many find this simpler than the two-step Extended kbd method.
To install the esperanto keyboard, copy the files "esperanto.icns" and "esperanto.keylayout" to the "Keyboard Layouts" folder in your Library folder. Then you will be able to select "esperanto" as you would any other keyboard.
files: esperanto.icns and esperanto.keylayout