2 is an application library for Minecraft. It is minecraft moving bookshelf foundation of the majority of current mods of Minecraft and developers can customise Mincecraft based on it. To do this, the staff of Forge have always updated versions to make mods compatiable with the update of Minecraft. Make sure you have installed Java in your computer.
Open the file using a java running program. It will bring up a menu. Make sure you have run Minecraft at least once. Pick the Forge profile and launch the game. Minecraft Forge will be active in your game.