The Moka Express is a pressurized coffee maker created by Alfonso Bialetti in Italy 1933. The name comes from the Yemen port city of Mocha, a major coffee hub at the time, which is famous for their pale yellow arabica beans. It operates by boiling water in a lower chamber, creating pressure and forcing the water and steam through finely ground beans into the top collection chamber.
Moka coffee lies somewhere in between drip coffee and traditional espresso in terms of flavor, strength and concentration. Bialetti still makes the same exact model with the only modification having been adding a safety valve. You can buy one in several different cup sizes. I use the 3-cup model. It produces 6oz of concentrated coffee which I typically dilute with 4-8oz of heated oat milk. I recently switched to oat milk and quite like the creamy, nutty aftertaste it leaves you with and it helps save humanity.
In Italy, Moka pots are commonly used to prepare caffè lattes, which are a breakfast drink of moka and heated milk. Traditionally, the milk is not frothed like in my picture, but can easily be achieved with an electric hand frother.
For my model, which comfortably makes two 6oz cups in the morning, I weight, then grind, 24 grams of beans. You want a fine espresso grind. On my Sette 270 that's about size 17.
Ultimately it's a volume recipe -- you just fill up the cup with grounds. Make sure not to pack it or you'll find out why there's a safety valve. Also, I'd suggest ordering an extra rubber gasket because inevitably you will forget to add water, put it on the stove, and realize your mistake when you smell burning rubber.