What are the rules or guidelines for Buddhism?

The guidelines would be what's known as the Eightfold Path.

(1) Gaining a more accurate view of the world (insight)

(2) Correct thinking and resolve (compassion)

(3) Thoughtful speech (avoiding lying, slander, gossip, time-wasting chatter)

(4) Compassionate action (the basic morality of harming none, not taking that which is not given)

(5) A well-chosen livelihood (that incorporates the rest of the path) and living within one's means

(6) Steady effort -- neither letting yourself off too lightly nor striving too hard

(7) Developing focus through meditation

(8) Learning to keep awareness in the present instead of drifting into dreams of the past or the future.