Category display styling

I have a set of posts from one category which I have to display on one page and to make it more visually appealing. It could just be something like a grid display of post thumbnails with links.

I’ve tried a couple of portfolio plugins, but they didn’t suit me, mostly because of the slugs.

I need links to be in the proper form, category/item, not portfolio/category/item.

Is there a plugin that could do something like this
https://bambootheme.com/showcase/jul09/

I’ve tried this, but the code doesn’t work for me – “unexpected ***” errors.

I just need to present posts in a nicer way.