Symbols & Collection Items not linking to elements


I am trying to create three pages, one for my projects in my portfolio, a blog page, and a page to showcase my work from within school.

Each needs their own subcategories so when people go to each of the three pages, they can click on a button pertaining to each subcategory to see the correct items within them. I would be very grateful within linking each of the three different CMS Collections to each of their respected sections on the three different pages and help to change the content within the sections of each of the pages so they do not mirror each other across each page and are instead separate entities.

Thank you sincerely for your help!