Need Some Help Editing the Jello-Wala-Mello Theme by Small Potato

Hello all,
this is my post in the forums so I am unsure what the response rate is like, but I hope someone could help me out.

I am currently using the Jello Wala Mello Theme and I would like to make the homepage, index.php, display three columns of posts (belonging to different categories) as opposed to just listing all my posts. For example, if you look at my site now: https://patrickdevivo.com/, you will notice that below the “featured” post all my other posts are listed by date. Is there a way to divide the main body area of the design into three different columns and have each one only display posts from a certain category?

I’d love some advice on how to do this, please take a look at the theme files so you can have a better understanding.

Thanks,
Patrick