you download the installer for forge and install it. then you make a mods folder in .minecraft. put the .zip file mod inside the mods folder. Open your launcher. When you open your launcher there is a button that says new profile. Name it whatever you want and where is says Use version, Choose Forge ......... Then boot up minecraft with that profile. You might have to login again. Then forge will boot up and there you go. A little tutorial on how to install forge and mods