Well, it’s certainly not rocket science, but it does require some study. Check out those links Dave provided, and see how quickly you’re able to grok it.
You might be surprised at how quickly you’re able to grasp the basics. From there you’ll want to hone in on the technique of Motion Tracking, in particular the use of Mocha, a separate application that’s bundled with AE. There are tons of tutorial resources for this on the web.
When you mention 3d text, it’s important to differentiate between text which has real edge depth, and flat text that moves in 3d space. Both are possible in AE, but edge depth requires some creative hacks or 3rd party plug-ins.
As for making the text “blend-in”, read up on Grain Matching, Transfer Modes, creating “Grunge”, the use of Lights and Light Wrapping, etc.
Best of Luck in your studies!
Joey Foreman
Editor/Compositor/VFX Artist