how to add this type of sidebar in generatepress

Hi there,

GeneratePress . com support forum uses the Customizer > Layout > Container ---> Content Layout: Separate Containers.

The Customizer > Colors > Content background is set to a transparent color.

And then this CSS to add the radius corners:

.sidebar .widget,
input[type=email],
input[type=number],
input[type=password],
input[type=search],
input[type=tel],
input[type=text],
input[type=url],
select,
textarea {
    border-radius: 5px;
}

I am sorry, I am asking for how to add recent posts in siderbar like this website has

The site is using this plugin:

https://en-gb.wordpress.org/plugins/recent-posts-widget-extended/

this plugin is not working with latest version of WordPress. Is there any other method.

I tested that plugin on 5.3 and had no problems with it. Maybe another plugin is conflicting.
The only other posts plugin i use is WP Show Posts:

https://wpshowposts.com