How to play minecraft mods for different versions?

So, i want to download a mod that's for 1.6.2 but the current version is 1.7.10. How can i still play it?

Guest

Open your Minecraft launcher and sign in. On the bottom left-hand side, click either "New Profile" or "Edit Profile." Under 'Version Selection', click the drop down menu and select the version you want; in your case, 1.6.2. Click "Save Profile." Click "Play." Your game is now running that version Minecraft!
If you need further help installing the mod, I would suggest MagicLauncher: http://www.minecraftforum.net/...ds-options

Nathan