Separate description for each category in a squarespace blog

I have a single blog page with 3 categories. When a user navigates to a category, I want them to see a description for only that category. Currently, I have only been able to make a blog overview for the entire blog page - not for individual categories. Is there a way to do this?

Yes, assign the posts the category you want, then create a page and place three summary blocks on it, each pulling content from your blog and each filtered by category, so each block has items grouped by that category. You then make this page your front-facing "blog" page and put the main blog, which contains the posts, in the unlinked section of your site. You name the summary block page "blog" and rename the main blog, "blog posts" or something similar. The summary page replaces the main blog on the NAV bar. It all looks the same to the visitor but the content becomes very different. I use something similar to this for my blog which contains many categories and multiple posts grouped by category and all tied together with a drop-down blog-post by subject menu. You can take a look here if you wish, just click the blog button. 

Derrick's random views

Thank you for your answer. What I'm looking for is three separate "pages" - one per category - that users can navigate to, where each "page" has a description of that category. ("Page" is in double quotes because it need not be a squarespace page, but even just a link to a collection of blog pages will work).

With your suggestion of summary blocks would I just create three separate front-facing pages, each having their own description at the top?

Further, don't summary blocks restrict the max number of items displayed to 30? Is there a way to increase that limit to show all posts in a given category?

We can use some CSS to do this, I guess so. So if you share link to 3 categories, I can check & give you CSS code.