When the window pops up, you will see what the other already drew and you will be able to start drawing. The others will be able to see what you draw. You can change the draw tools by selecting an icon on the left. If you select the image paste mode, you will be able to select an image from the Como Server's directory. Currently, you can not paste your own local files due to netscape's to restrictive security policies.
Push the DEL key to delete the last object you drew. The first one to join this channel will be able to clear the board if necessary.
In most draw modes, you can hold down the meta key or use the right mouse button to constrain the object you create to a circle, rectangle, or image with correct aspect ratio etc.
If you select "Owner's" in the Color mode choice at the bottom on the left, you will see the objects everyone drew in their respective colors. Users who have left will be displayed in italics and removed the next time the board is cleared. That way, you can still see what they drew after they left.