Let's say the ALJ denied you on based on three things. The Council decided he was incorrect about item 1 & 2. At the remand, he must take their decision and apply it. It also doesn't mean that the ALK proceeded through all the steps. As soon as he found sufficient evidence to deny you, that was it.

You have the burden to PROVE your disability. This is a complex medical/legal evaluation. You are getting another opportunity to do so.

The ALJ must provide a new decision but it's not necessarily a slam dunk approval. You proved the ALJ made an error of law, you did not prove your case should have been approved--either partially or fully.

I only understand this because I represented myself and dug in to learn how the system. I hope this was a clear enough explanation. If not, maybe someone else can do a better job.