To make this work you need to either heat the water in a reservoir above the grounds, or actively pump the water to above the grounds. Most cheap makers do neither. This one has a pump. Another advantage of the pump on this one is that you can adjust the flow rate.
There is kind of a sad story about these. They’re based on 19 century designs, but they were reintroduced in the 1990s by a clever, very nice Belgian craftsman, Patrick Van Den Noortgaete. However, as they became popular his designs were copied by Chinese manufacturers, who then managed to outcompete him and put him out of business. “Royal” was his name for the line, so if you ever wonder why these things are called “Royal” and “Belgian”, it is just a way of preserving their ripoff heritage.
In addition to the traditional design, Patrick also sold one in a contemporary design; I bought one once as a wedding gift for a friend:
