I put the actions that are not the NEXT action in one of two places:
1) On the Projects list in a note attached to the project.
2) In certain (simple) cases, in the note attached to a next action. For example, say I am going to call Joe and then call Sam to tell him what Joe said. In @Calls will be a task to call Joe. In the task's note, I will have "Call Sam re: conversation with Joe."
In your example, step 12 of 30, I would put that list in the note attached to the name of the project on the projects list.