HTML Blocks – How to add categories to this to help split large amounts of them

As the title says, how can i extend the custom post type in the woodmart core plugin or outside if possible to ensure changes aren’t overwritten? I’ve looked at the code and tried to modify but can’t get it working, I can add another totally new post type with categories though so know it can be done, I’d rather update this one though.

Is there code elsewhere that needs modifying as well?