how to create this pattern?

Hi,
I want to create a website with a special feature and use,
the page should be at full width (without empty spaces) and it will be full of rectangles in all rows and columns which are used to show ads! first customers fill a form and upload their image and write their ad texts, then when the payment is done, automatically a rectangle gets created and their image and text gets inside of that rectangle and is shown. so the page is full of this rectangles and at the top of the page there are some buttons which are in fact categories and can change the ads group.
I don’t know how to create it and which theme and add-on can make it done, please help.

here I draw a simple of what I mean and want to build.
https://files.fm/f/2yh3qymk