We have added our widgets as plugin which is also built into the theme. Here is how to enable it to use.
Go to Dashboard > Appearance > Install Plugins
Now click on ‘Install Plugins‘
After you have installed, go to Plugins section and ‘Activate’ Magazine3 Widgets plugin
Now go to Widgets from the ‘Appearance’ section and you will see list of all the custom Magazine3 widget.
and That was it!