How to Add a Sidebar to a Wordpress Theme

I recently needed a little more control over the sidebar on a theme and had never added a sidebar to a theme before. I wanted certain widgets to show up only on posts and the rest to show up on posts and pages. The below is how to add the sidebar:

In the functions.php page, we need to modify the code which looks like this:

To make it look like this:

Now, when calling a sidebar, we just need to call it by name as in the following:

Obviously we have freedom to name our sidebars as we please. Look for more info on making a sidebar only show up on posts in an upcoming post.