Hello,
1) If it is a custom page, create a custom sidebar via Appearance > Widgets > add text widget with links or static block with the desired content, then set this sidebar on the page http://prntscr.com/t2r4sz
2) Widgets of Shop page can be changed via Appearance > Widgets. Settings of the sidebar you can find in Theme Options > WooCommerce (Shop) > Shop > Shop page layout.
Regards