Learning with CI2 Tutorial, but using CI3?

There are quite a bit of changes between 2.x and 3. As you probably know, 3 hasn't officially been released yet, so there aren't many tutorials floating around for it yet. I'm sure once it's released that will change. It shouldn't be too much longer as they're into the Release Candidates now.

But the best place to find the differences is in the userguide to upgrade from 2.x to 3.
http://www.codeigniter.com/userguide3/in...ading.html