The expression, "on the behalf (behalf) of someone" means that you are speaking for another person or another group, that you're expressing someone else's opinion or thoughts.
In this case, Alex is thanking Shawn, and he's also expressing the thanks of everyone else in the room - "on behalf of" everyone in the room.If you are a team leader, for example, and your team receives an award, you might say, "On behalf of all my team, I want to thank you for this award."
Alex is thanking Shawn for leading an interesting and productive meeting.If something is "productive" (productive) it's effective in getting work done well and quickly.
For example, if you type 100 words per minute, you're probably more productive than someone who types 20 words per minute, because you can type more quickly.A productive meeting, then, is a meeting where the people are able to get a lot of work done and they feel it was a good use of their time.
Alex says, "I think we have all learned something here today and we have a clear action plan for the next steps."An "action plan" is a plan or a list of what you are going to do that tells you each part of what you need to do.
We would say that gives you a "step by step" for doing a project over a certain amount of time.First you do this, then you do that, then you do this; it tells you what you are going to do in the future.
That's an "action plan."The action plan for Vision Corporation is to work in two committees, or small groups, on the marketing campaign and on the product changes.
A "next step" is the next thing that you need to do, or that you will do.Your next step after listening to this lesson, for example, may be to read the transcript over again.