How much is 1 GST to a HKD?

Excuse me, I was wondering if you could clarify something for me. I've been looking into the current exchange rates and I'm a bit confused about the conversion between Goods and Services Tax, or GST, and Hong Kong Dollars, abbreviated as HKD. Specifically, I'm trying to understand how much one unit of GST would equate to in terms of HKD. Could you please elaborate on the methodology for making this calculation, and provide me with an approximate figure for the current exchange rate? Thank you for your time and assistance.