At this point you have already told the audience what you were going to tell them (in the Summary section), and then you told them (in the Results/Discussion section). Here you simply want to recap what your main findings were. Specifically you want to first tell them whether or not the objectives were reached. If they were fully or partially reached, you want to summarize the key findings, and you want to point out any weaknesses, or assumptions in those findings. If they were not met, you want to explain why it was not possible to reach the objectives (identify the major sources of experimental uncertainty). One visual is usually enough.