想當一位翻譯員...

Apart from being very fluent in the languages you are interested, you also need to take translation courses and get qualification. There are different courses. For instance, if you want to translate from English to Chinese or vice versa, you need only to do "one way translation" courses. If you want to be able to translate from English to Chinese AND vice versa, then you need to do "two way translation" courses. There are also different courses for oral translation or written translation etc.

Unfortunately I am not sure where in Hong Kong you can get these courses so I can't help you there. However, if you know where you can find these course, please do let me know.

中英文要A
學多几种語言有幫助 ga