how to get from casa hotel to lantau island big buddha, im staying at casa hotel yau ma tei, Hk

There is no direct transportation between these two places. You need to transfer.
Take Tsuen Wan Line at Yau Ma Tei Station, and get off at Lai King Station. Then take Tung Chung Line to Tung Chung Station. After that, walk to Ngong Ping cable car station to take the cable car to your destination.