Link to product caterogies

Site URL: https://www.moscowdrugclub.com/merch

Hi, 

I'm trying to do something very simple, but can't figure it out! 

On this page: https://www.moscowdrugclub.com/merch

I want to be able to link to the product categories, so that when someone clicks onto it it takes them to all of the products in that category. At the top of the page I've written the three categories (T shirts, CDs and downloads).  We then have a little section below for each category with a 'shop now' button. 

I'd like to be able to click on T-shirts or the shop now in the shirts section below and it links to all of the t-shirts. The same for the other categories too. How do I create a link to a category like this?  Or is this not possible?  

Many thanks in advance,

Andy