You can take Subway Line 1 at Songdan Station to Tiananmen West and walk to the soutweat corner to catch the bus at Beijing Tourist Dispatching Hub to the Great Wall. Or take Subway Line 5 to Yonghegong and change to Line 2 to Jishuitan, walk to Deshengmen to catch the tourist Bus 919 direct to Badaling. Take 919 and get off at Changping where to change Bus 314 to Ming Tombs.