So. The minecraft project… (I'm a fan, too) he's actually using a modpack, (at least the newest season is) which means that he didn't actually mod that entire thing himself, its all these mods put into a pack that he downloded. (called 'feed the beast', you can search it up to find out more.) if you just want a couple of mods, you'll have to downgrade to a lower version - 1.6.4 or lower (because most mods arent updated to 1.7 yet) it sounds scary but it's easy. Just launch minecraft and in the bottom left it says profile:, new profile, edit profile.
just click new profile and where it says use version: just click release 1.6.4.
search up a video on how to install mods with the new mc launcher, its hard to just explain in words.
another way thats much easier imo, is to use the technic launcher, which you can link up with your minecraft account and install modpacks from their website ( some of which are feed the beast, aether, tekkit etc.)