I am here to study : purpose of your stay

Hello every one !

I'll be leaving to HK very soon and I would like to be able to explain why I'm there. Note that I hardly speak any Cantonese, but I feel familiar with the grammar since I've been learning Mandarin for 6 months.

So my question is : how to say "I am here to study", or in a more general manner how to give the purpose of you stay.

I'va already found some translation for :
I am here on holiday : ngo5 lai4 nei4 dou6 dou6 ga3 ?
to study : duk6 syu1

Does it seem correct to you ? Can somebody explain how the first sentence is built ? How to combine the two ?

Thanks in advance !

Kaldo