Its not working

Hello @juanroggia,

Sydney Toolbox plugin is not designed to add widgets. Here is the plugin description:

This plugin registers custom post types and custom fields that are needed in the Sydney theme

Please create a topic on Sydney support forum if you need help:
https://athemes.com/forums/forum/sydney/

Also you can check Sydney documentation here:
https://docs.athemes.com/category/8-sydney

Kind Regards, Roman.