How to displye category posts on homepage?

Hi Shiraz,

If I may suggest, here are the steps I would take to do that.

I'd consider creating a custom post type (if there's no knowledge base post yet) or taxonomy (if the knowledge base posts are already made) for "Knowledge base".

You will then associate the posts to the "Knowledge Base" taxonomy or post type and then get a post listing plugin like WP Show posts.
https://wpshowposts.com/

With WP Show Posts installed, create a post listing for the "Knowledge base" taxonomy or post type. After saving it, get its shortcode.

You then add a shortcode block with WP Show posts shortcode in it on the sidebar widget area. After adding and saving, a post list of your knowledge base items should display on the sidebar. :)