hello trapper48, please see if you can add the button described by [[Customize Firefox controls, buttons and toolbars|customizing the controls]] in firefox - or in case this does not work, please contact the developers of the addon directly to get support, since they can likely give you more detailed guidance on how to use their product: https://addons.mozilla.org/firefox/addon/similarsites/

Thank you madperson "customizing the controls" led me to where i could add the icon.