I created a custom sidebar using Appearance sidebars and widgets. I want the sidebar to appear on my St. Louis page responsively. However, the sidebar does not appear in the registered widget when using the widget element so I can not assign it to the page. The goal is to have the sidebar appear on the left side at the first three break points and at the bottom of the page at the two smallest breakpoints.
Do I need to add code to the child theme to register custom sidebars or how do I register them?