Hi, you can take bus at Hangzhou West Bus Station or Hangzhou Tourist Center, it costs CNY95 to CNY100 for 3 hours. There are 6 buses can take you directly to Huangshan Scenic Area everyday from 08:00 to 15:10. If you missed the bus, you can take bus to Huangshan Tunxi and change to bus to Huangshan Scenic Area after arriving. There are 13 buses to Tunxi and the last one is at 18:20. There is one bus everyday from Hangzhou Tourist Center, it departs at 07:20 and it takes passengers directly to the scenic area. BTW, Hungshan is what you called Yellow Mountains. Good Luck!