Worksheets, such as "Hidden Word Game", "Fill in the Blanks" and "Match-Ups" are meant to be a self-testing means of letting the students find out how much they know. They can be used before or after the astronomy lessons and planetarium show. Using them early may help generate interest in astronomy. Using them later may help show the students how much they've learned.
The Discussion Questions are probably best used in small group or whole class discussions. These questions do not have "right" or "wrong" answers; they are meant only to generate interest and start a thoughtful discussion about difficult issues.
The Research Questions are meant to be used for exactly that; research. Most students will need to use a library or computer sources to find the answers. They can be divided among the class so each student will end up with a different paper or oral presentation.
The Summaries, such as the Space Flight Summary, have no specific student activities.