If it's anything like Kopi Bubuk from Indonesia (fine as literal flour), then it's meant to be brewed in the cup. Simply put a heaped tablespoon into a mug, fill with boiling water, stir it for a second, let rest for a bit, stir it again, let rest until all grounds sink to the bottom, and then drink it carefully. You'll still drink some grounds, but they are so fine it hardly matters.

Indonesians drink this type of coffee with a bucket of sugar and often condensed milk, but that's optional. I enjoy it pure, and keep buying it whenever I'm in Indo, as it's hard to find elsewhere in the world.