What's the best way in going about writing a reflection letter?

I had a guest speaker in my Lessons of Vietnam cl on Friday and we were asked to write a one page reflective letter to send to the speaker. I know it's not supposed to be one long paragraph, but I think the maximum amount of paragraphs should be three. I am not really sure how to start if off and what to put in each of the paragraphs. I was thinking the first paragraph be about what a guest speaker means to me, then the second paragraph be about what I learned, and the last one be about wishing them luck in the future. How does that sound? What do you recommend? Thanks