Help me implement a Post Grid (Pinterest style) on my website

I have a WordPress website, and I'm looking for a free plugin or just the code for a Post Grid, like the first one in this site: http://ift.tt/OYqNW6

Try keep it simple if possible, as I don't have much experience on webdesign in coding in general.

Epic visual tool

Epson 5030UB 2D/3D 1080p 3LCD Projector Submitted March 27, 2016 at 06:07AM by bastos944 http://ift.tt/1oe9XJW