How to go from Novotel Citygate to: 1. Ocean park. 2. Central, Hongkong. 3. Mongkok?

To Ocean Park: walk from your hotel to Tung Chung MTR station and take the Tung Chung line to HK Station. Walk through an underpass to Central Station and then move further to Central Pier no. 7. There you can take bus no. 629 to the park front door.

To Central: follow the above way.
To Mongkok: you can still use Tung Chung line and should get off at Lai King. There you can change to Tsuen Wan line to Mongkok straightly.