The two ways matcha is prepared. Usucha, thin tea, is about 2 g of matcha to 60–70 mL of water, whisked to a foam. Koicha, thick tea, uses the same 2 g to roughly 15 mL and is kneaded rather than whisked, with no foam. Everyday 'making matcha' means usucha.
In more detail
The difference is not only the ratio: the powder itself is chosen differently. Koicha calls for tencha from a longer shading period, which carries less bitterness at that concentration. In the tea ceremony a single bowl of koicha is shared around, while usucha is made one bowl per person. If you want to try koicha at home, the first thing to know is that usucha-grade powder will not do it.