I don't recommend starting an event with logistics; however, I do suggest asserting your mission.
The one thing that will fuse you, your team and your audience will be your mission — the cause, belief, or intention that drives your action.
When we assert mission, we not only understand our goal but the "why" behind the goal — we feel it.
If you want to inspire people to act, start with your mission. Assert who and why we are and what we are meant to do. Make our gathering matter.