Would you please help me to have a convenient itinerary of 4 days of stay in Hong Kong?

Well, you can arrange the four days sightseeing in the following way.
Day 1: Lantau Island, Ngong Ping 360 & Big Buddha
From the hotel, take bus no.E31 at Bo Shek Mansion, get off at Citygate. Then walk to the Cable Car Terminus and take it to get to Ngong Ping 360 and the Big Buddha. The return way is the same.

Day 2: Victoria Peak & Madame Tussauds, Victoria Bay, Tsim Sha Tsui & the Symphony of Lights
From the hotel, take Tsuen Wan Line, get off at Lai King Station. Then transfer to Tung Chung Line to Hong Kong Station, Exit C. After that, walk to Lower Tram Car Terminus and go to the Peak directly by tram. The Madame Tussauds is close.
To the Bay and Tsim Sha Tsui, take the tram car to come back to Central Station first. Then take Tsuen Wan Line to get to Tsim Sha Tsui Station, Exit D1.
Back to hotel: Take West Rail Line to Nam Cheong Station. Then transfer to Tung Chung Line to Lai King Station and Tsuen Wan Line to Tsuen Wan Station, Exit B2. After that, walk southeast around 160 yards.

Day 3: Wetland Park, Causeway Bay
From the hotel, take bus no.269M at Chung On Street Tsue Wan, get off at Tai Lam Tunnel. Then take bus no.967 at Tai Lam Tunnel Toll Plaza, get off at the Wetland Park.
To Causeway Bay: Take bus no.967x to get to Lee Theatre Plaza, Percival Street. Then walk northeast around 130 yards.
Back to the hotel: Take Island Line to Central Station. Then walk to HK Station to take Tung Chung Line to Lai King Station and Tsuen Wan Line to Tsuen Wan Station, Exit B2. After that, walk southeast around 160 yards.

Day 4: Disneyland Resort, Central Area
From the hotel, take Tsuen Wan Line, get off at Lai King Station. Then take Tung Chung Line to Sunny Bay Station and Disneyland Resort Line to Disneyland Resort Station, Exit A.
To Central Area: Take Disneyland Resort Line to Sunny Bay Station. Then transfer to Tung Chung Line to Hong Kong Station, Exit C. After arriving, walk southeast around 130 yards.
Back to Hotel, take Tung Chung Line to Tsuen Wan Station, Exit B2. Walk southeast around 160 yards.