customize edit page and post box

hi, how do you customize the post page? for example, a pinboard theme, or anything like pinterest theme, on the main pages there are many post images boxes, i wanted to customize the elements of the boxes?

and also how do i customize the users edit page before they post? for example before a user post a page, they were in editpage, they put the description, etc etc, i wanted to add some elements on it like, url link, or country text box, contact email or number, any custom elements that i wanted to add.

thankyou very much