Student or Learner
Please make the following in red clear for me.
To his surprise, he learned a great deal from his experience, a real treasure trove of insights and impressions that completely changed his approach to his concept for his green project. For example, his greatest takeaway from the experience was that the design of the project should not only be green but create functional outdoor workplace.
Does "takeaway" mean "lesson" in the context? And is the second saying "the plan of the project should be environment-friendly"?