Forge Download
Select the minecraft forge 1.7.2 recommended version installer.
Taken from [URL|files.minecraftforge.net/] (I don't take credit for this image, besides the arrows)
![[MAC] Minecraft Launcher](https://media.forgecdn.net/attachments/126/915/MCForge_Installer.png)
[MAC] Minecraft Launcher
Select 'Profile Editor', then select the 'Forge' profile, then click 'Play'.
Taken from the minecraft launcher (I don't take credit for this image, besides the arrows)
MC Launcher
Select 'Install Client', then 'Ok'.
Taken from Mojang's Minecraft launcher (I don't take credit for this image, besides the arrows)