In our drill work we will line up in our normal alignment.  In this drill the ILB is lining up over the center.  Key progression is about taking your step and reading your key.

The next video is really just about keying the base block look and plugging your gap of responsibility.

The next two videos are from the Philadelphia Eagles and we will eventually have two linebackers going together to work on the key progression in more of a simulated aspect and then with DL.  What I love about this is, the basics are done at every level.