How to catch a bus from chungking mansion to Disneyland?

No direct bus runs between these two places. So you are suggested to take subways.
You can take West Rail Line, get off at Nam Cheong Station. Then take Tung Chung Line to Sunny Bay Station and take Disneyland Resort Line to Disneyland Resort Station, Exit A.
It takes around 40 mins. And the fare is 20 HKD per person.