@Jennifer141 the only way I can think of to send the guests your policies would be to use a saved message in response to reservation requests. Here's some info on saved messages:
http://blog.airbnb.com/messaging-made-easier
By the way, what's different in your policies from what's in your house rules? If possible I would incorporate these into the House Rules so if there is a problem, Airbnb can see what you have on your listing. With a separate agreement, you're on your own. Airbnb cannot and will not enforce policies that you and the guest enter into outside the listing details.