Bus routes cover most part of Hong Kong, there are 4 bus companies operating different routes. Bus Final destination are being shown in English and Chinese on the front of each bus. Note that route number being used in Kowloon side can be reused on Hong Kong Island side, vice versa, but they run at distinct district hence you won’t get confused.
Since bus is a very local public transportation many drivers may not be able to speak fluent English, hence it is better for you to know where to get on/off the bus. You can show/tell the driver your destination (better in Chinese) so that they can notify you when arrive. Locals are also happy to provide assistance.
You can use Hong Kong eTransport App to find out which route to take as well as the bus stops you are getting on/off the bus.
Octopus Cards are accepted on all bus but exact change is required if you pay by cash.