How can i learn to jump?

I just got a 24 year old 15.3 hand mare. shes my first horse shes been out of for 9 months she used to be a racehorse and then was a riding school horse for 10 years my friend bought her but shes moved to a more energetic horse, its my first time jumping and im not sure how to and i really dont wanna hurt my horse so has anyone got any tips.