Customize Category block module prestashop

I need the category block menu customized, with the following; When hover over the categories it show the category image instead of the long category description, or if possible the category image and a short description of the category. I have 2 levels of sub categories, I would like to have the menu show the main categories and the 1st level of the sub categories always shown as default. Then when clicking on subcategory, it will open the 2nd level.