Mega menü and Product layout on overview pages

Hello community. It’s good to be here. I have two concerns. I’m creating an ecommerce page with the oxygen theme. First I would like to create a mega menu. But I can’t do it. How do we do it? Secondly I would like to have on my shop page just the pictures, the name of the product and the price without the other attributes like size and color. How does it work?