Step down with glutes
Once you've got the hang of the step up with glutes, and can do that consistently and well (say, 3 sets of 20) then it's time to move on.
The further forward you take your centre of mass, the more of a challenge it is for most people to maintain gluteal control. And the easiest way to move your centre of mass forward is to move your other foot forward - in other words, progressing to a sideways step up, and eventually to a backwards step up/forwards step down.
The trick with this exercise is that it must be pain free and it must be controlled. If you can't maintain alignment of your foot, hip and knee throughout the whole of the exercise, then you need to move your bottom foot back a bit!
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