Portfolio Help – Please

Definite newbie to wordpress! I’d appreciate any help on this. I don’t know how to create this portfolio-whether to use a page or portfolio-item. I installed the dummy-data which is very helpful and I am trying to modify to work for me. I want to have hierarchy of PROJECTS with different sub-categories like COMMERCIAL and EDUCATION. I want to display a page like the PORTFOLIO 4 COLUMN page and only show pictures for that subcategory. How do I do this? Can’t find the PORTFOLIO 4 COLUMN PAGE. Do I need a separate page for each subcategory? When the use clicks on a picture, I was able to create a portfolio-item to display the information about it. Thank you!