Using portfolio categories on home page

Hello,

I have a teaching website offering 3 levels of courses taught online and face to face. My current set up is:

– Portfolio categories are set as Level 1, Level 2 and Level 3.
– Within each of these levels are two Portfolio items – which are the teaching method: online or face to face, which are displayed on the website using the masonry grid.

User should select level first, then the teaching method. But I currently have portfolio items showing on my home page and I am struggling to introduce the categories and this flow. How can I add the portfolio categories onto the home page and link them to the items, so when you click on Level 1, it gives the user the portfolio item options of online or face to face?

Is there a smarter way to do this? Or a plugin that helps? Hoping this is a simple fix.

Thanks