Okay, so I looked up how to install mods. I want to get the Biomes O Plenty so that it works in minecraft. I did absolutely everything the instructions from three different sites told me to do and triple checked to make sure it was done. The thing is, when I run Minecraft, the mod won't work! I have Minecraft version 1.7.10 and the mod I downloaded is for that version of Minecraft. I also have Windows 7. Please tell me what I'm doing wrong, if I'm doing anything wrong. I don't know how to get it so that when I play the game, it will show up with the mod working.
Biomes O plenty is a mod that alters the generation of the minecraft world.
To use it after installing it you have to create a new world, go to options and set the World type to "Biomes O plenty".