Some classic beginnings facilitators use include establishing the focus by using a short video clip – perhaps from YouTube; stating the focus and encouraging exploration by asking people to work on some aspect of it in twos, threes or small groups; working with some of the participants beforehand so that they set the scene by making a short presentation; and summarizing where the group had got to in the previous session (if there was one).
This seems very practical and helpful for developing a facilitation guide.