Index posts

Good morning,

I wonder if someone could point me in the right direction. I’m redesigning our organisation’s site which is used for doctors to find out information about different specialties. I’m using Divi by Elegant Themes.

There are a number of specialties (which I currently have set up as categories, such as Cardiology, Allergy, Dermatology etc.) and within that, I have posts for each condition (eg Cardiology – Atrial Fibrillation, Cardiology – Palpitations, Dermatology – Acne, Dermatology – Lipoma etc.)

I’m trying to find a way to index these so that the site functions by going to a page which lists all the specialties/categories with an expandable sub-list of conditions/posts.

I’m sure this is a pretty basic ask, but none of the plugins I’ve found really work as I’d like and I wondered if anyone had a neat, clean way of doing it.

Many thanks