I need to go from HKIA to Cumberland Road.

Well, there is no direct public transportation between these two places.
So you are advised to take bus no.A22 to Chi Wo Street, Jordan Road first. Then transfer to bus no.7 to St.George Apartments. The whole way takes around 65 mins. And the ticket fare is 43.9 HKD per person. After arriving, walk northwest around 550 yards (500 meters) to find the destination.

Hi again,
Is there any bus that goes direct to Kowloon Tong station ? I need to go an address that is on Kent road which is very near the Kowloon Tong station.

No, you still need to transfer. Maybe this time you can try to take the metro. From the airport, take airport express to Tsing Yi Station first. Then transfer to Tung Chung Line to Lai King Station and Tsuen Wan Line to Prince Edward Station. After that, take Kwun Tong Line to Kowloon Tong Station.
The whole trip takes around 55 mins. It costs 60 HKD per person.

Dear Rang,
Actually there is the E 22 bus which will take me very near Kowloon Tong station. Then its a few minutes walk.
I checked online for the citybus route and found that answer.
I will be there tomorrow, so i will update you further about whether that information was correct or not, after i return from my trip to there by next weekend.

Many thanks for your help :-)

Hi rang,
So i was correct from my readings online.
The E 22 bus ( HK$ 18 ) will take u near kowloon tong station. U ask the driver which stop to get off ( i remember its the 16th stop) and then its a 10 minute walk to kowloon Tong station.

It is very convenient and it takes a maximum of 45 mins in either direction.

Thanks once again for your help :-)