1. Please go to Youzify Panel >> General Settings >> Wall Settings
2. Select any Sidebar Layout on the Activity Stream layout box
3. To add widgets on the Sidebar, please go to Appearance >> Widgets. Drag n drop any widgets you want to the Activity Stream box
PS: For some server, the new WordPress Widgets Settngs is not load well. We sugegst you to install this plugin to restore WordPress Widgets Settngs to the classic version
https://wordpress.org/plugins/classic-widgets/