How to add a sidebar to any page
There are two ways to add a sidebar to a page. The first one is through the Customizer area, and the second one is through the individual page setting.
How to add a sidebar through the Customizer area
Setting a sidebar through the Customizer area will make every page in your website have a sidebar by default. On your WordPress dashboard go to Appearance » Customize » Posts/Pages Layout.
Click on the page where you want to add a sidebar onto. I’m going to explain a little bit of the terms used on each of these tabs.

Page layout – your individual general page
Single post layout – your individual blog post
Archive layout – your blog posts archive
And the following are added features that come with your SheShoppes-Kadence Premium Plugin:
Podcast layout – your individual podcast post
Podcast archive – your podcast archive
Portfolio layout – your individual portfolio post
Portfolio archive – your portfolio archive
Click on the tab where you want to add a sidebar to. For example, I’m going to add a sidebar to all of my pages by default. So I click the Page Layout tab, and scroll down to the Default Post Layout settings.

You can choose the left sidebar or the right sidebar option.
By default, it assigns Sidebar 1 to that sidebar. You can change this part to Sidebar 2 if you wish to have that one instead.
Depending on which sidebar you chose, you will need to add widgets to that sidebar for it to show up in Appearance » Widgets.
How to add a sidebar through an individual post or page settings
On your individual post/page editor, you will find page settings), you have page layout options. Some of the layout options include a sidebar.
Adjust the width of your sidebar
Go to Appearance » Customize » General » Sidebar. Under Sidebar Width, change the % value to your desired sidebar width. If you prefer to set a fixed width (not a percentage), click on the % icon and select px. I personally prefer it between 25 – 28%.