In the last picture you see the entrance to their actual store. It’s tiny, but there’s not a lot that they need. I bought 1,000 HKD worth of bitcoins (~100 Euros) which turned out to be 0.20346785 BTC.
You can only buy bitcoins there not sell them. They say they are looking into enabling that as well.
To buy bitcoins there you need a government issued ID (HKID, Passport), email address and provide them with a valid address. They will then create an account on their online exchange and credit the bitcoins directly into your account there, rather then sending them to you directly. Given that it is a great place to buy your first coins and get your account verified, but in the long run you might as well deposit cash straight into their bank account (in Hong Kong banks allow that). It gets credited relatively fast manually. Things are going very well in Hong Kong right now!