Electronic Tax Reserve Certificate scheme

Someone mentioned to me that this will help the burden of paying your tax in 1 go and I wondered how it worked? Does anyone know a little more about it explain how it works?

For example if you make like 30,000 a month would you suggest to then get a tax certificate of 2000 or 3000 hkd monthly is that how it works so once tax comes in you can use that reserve to pay the amount of that has been bought through the scheme?

I also read there would be some interest we need to pay but I didn't fully understand it. Sorry new to this tax as I was lucky enough to have my tax paid in another country and having a whole chunk of payment in 1 time for tax was quite painful :) so wondering if someone to help explain.

Thanks again