How beginner of a lifter are you? You may not even need to worry too much about all this.
For phase 5, he’s just talking about the lifts themselves. Bench and overhead press (and their variations), row and pullups (and their variations). Just use good form and you satisfy that.
Phase 3 he’s just re-emphasizing good form. That point is completely redundant with phase 5. In some cases a trainer may prescribe something, but for most people, just practicing good form on each rep including their warmups is sufficient. For example, if you need to fix your bench form, you’re going to do it while bench pressing.
Rusin is a Dr., he’s smart and obviously qualified, but most of his articles are written from the stance of how everyone is physically wrong and needs to be fixed before they’re allowed to progress. His writing suits the soccer-mom/dad-bod/resolutioner crowd a lot better than serious lifters.
He gets punked on a little around here, sometimes unfairly, but his articles will also tell you to replace dangerous pullups with seated 1 leg elevated band facepulls to the mandibles, so, take it with a grain of salt.