The files you got are correct, MAIN, FS and Custom pack. But HONG KONG is for traditional Chinese.
Top Sony - Languages Description
You will need CHINA, China is simplified chinese.

And for flashing you will need the flash drivers.
I used XS++ to flash mine because it seemed the easiest:
XS++ 3.1 Guide-Flashing,Customizing,Recovering - Top Sony Forums
But you can use others.