To go there,  get on the bus bound for Haguro-Gassan (bus timetable) and get off at Haguro Zuishinmon mae 羽黒随神門前. 

You will need to go down Mt. Haguro's stairway to go there. The stone steps can be very slippery after the rain, so please watch your steps. Bring rainwear in case of bad weather, and water supply to prevent dehydration. 

Some people find Mt. Haguro's exploration to be a very physical exercise. Please make sure you are feeling well enough to walk Mt. Haguro's stone steps.