Set up Blog to Masonry Grid Style from Theme Options

hi
i know this is a newbie question but i am sure you would be able to help
i am trying to setup the blog and in your demo data the only blog is the full width regular one but i want mine to be in the masonry grid style but i have abseloutly no idea on how to achive this?
also in the blog page on the demo there are categiroes. is there a way to show the categories in a drop down button instead of as a list as the default?
thank you so much