How do I design the help center?

We recently bought Salesforce Essentials, being told it was an out-of-the-box product that requiered only a little configuration. That wasn't exactly true...

I'm trying to set up the help center, but I don't understand how to get it to look decent. I've tried different templates (I only get to choose between 5 different ones?) and still the component "Topic Catalog" (and the others) looks really bad.

I came across this article, but my page isn't even close to that, regardless of how many settings I change. https://www.salesforce.com/products/service-cloud/best-practices/top-support-center-designs/

Could anyone advise me on where to start? Do I need to do everything in css (so much for the "out-of-the-box"-thought) and where do I do this? (I tried to, but then SF told me that I should rather create my own component.)

I'm more than lost here, so any advice would be greatly appreciated!