I have cerebral palsy, how can i exercise?

Any way you can: Cerebral palsy is a disorder in the control of your muscles. Learn how to control them any way you can. Use you muscles and joints as much as you can to keep them healthy. Therapists can help you. Surgery may be necessary, but may be avoided. Work on doing daily activities yourself without help. You may need modified clothing, utensils, toilet, etc.

Depends on the type: Cerebral palsy is a disorder due to a static brain insult. It has many causes, an many manifestations. There are forms which can cause tight dysfunctional muscles, movement disorders or a mix of both. Additionally 1, 2, 3 or all 4 limbs can be involved. A physical therapist is best suited to recommend exercises ideally suited to maximize function.