What does iterating on design truly means?

Iteration is not revision for its own sake. There are two parts to it. In the critique process, you might jam together, someone might riff on an idea and push it further in real time. But then there is also taking it away and diverging again on your ideas. You might have gotten feedback and now you are thinking, how can I apply that and iterate to make the solution better next time?

You come up with solutions to push it further, and then refine and converge from that point. There is real time collaboration with people who have strong craft, and then there is also the process of building confidence yourself through diverging, coming to multiple solutions, and then converging on the one you feel is the best. Ultimately, it boils down to personal curiosity and the attitude you carry when you are working.