this is a texture pack texture packs changes the looks in minecraft like the blocks and items mobs and even armour. all you do is download the file and place it in your resourcepack folder in minecraft folder (C:\Users\Thomas\AppData\Roaming\.minecraft\resourcepacks) if you done have a resource pack folder go to (C:\Users\Thomas\AppData\Roaming\.minecraft) and make a new folder called resourcepacks no caps no spaces then place in the file. after that go to your minecraft launch it go into options then resource packs hover over _real life pack_ and there is a arrow click it then click done it will take a minute to load when you click done so be patient and dont click on minecraft again or it wil say not responding then its done and you can play your minecraft.
and if doing a showcase say made by MrCool1812 hope you enjoy have fun :D