Below is an example layout for the main room for an Open Space event:

As many chairs as there are participants, ideally in one but can be in several concentric circles

Cordless microphone(s) ready (one for facilitator and one as a backup, if the space and the group is large) -- checked to ensure that they are working and have fresh batteries

Single sheets of paper (for writing agenda/session topics - can be ¼-sheet chart paper or a ream of copy paper) and basket or pile of markers in the center of the circle (If you feel some in your group may have mobility issues, you can keep handy clipboards to pass out to those who may need to remain seated but wish to draw up topics)

Large signs (principles, law, insects, theme, be prepared) posted around the room

Smaller (or large) signs at the computer area - simple how-to notes for non-technical people, news room hours plus deadlines for entry completion. Newsroom sign to indicate the computer area.

Breaking News sign set up on a free wall where printed proceedings get posted.