How can i go from the downtown of peking to the great wall?

Oracio, which section are you planning to visit, Badaling, Mutianyu or Simatai? Badaling section is well preseved while Mutianyu and Simatai still keep their original looks. However, all people who visit Simatai section must make reservation on its official website. I am afraid that you can't do that because everything on the official website is demonstrated in Chinese.