hello, i tried to use su e xing to take metro in shanghai but it didn*t work.

You can check the guide here: https://mp.weixin.qq.com/s?__biz=MzA3NTYzNjM4NQ==&mid=2247550611&idx=1&sn=92d45abbeee1e28c6cd0cd3169d1152b&chksm=9f6fcd5da818444b084bd00034dc1cf86e5937ae5f13e6f4c5d4c037eac091dce0dd1e7386be&token=990948026&lang=zh_CN#rd

Remember to change the city first.