Eleo Seedri Latte jook is meant to be served hot, as a latte-style drink, rather than as a cold beverage. The simplest way is to follow the serving size on the package label, which is the only reliable source for the exact amount of the product per cup. Add hot water, stir well, and the drink is ready to enjoy even without anything extra; the product information notes that it already feels pleasantly creamy thanks to the cedar flour.
If you prefer a more conventional latte, replace part or all of the water with milk or a plant-based drink. Oat and soy drinks generally work well with roasted, spicy flavours, but any milk alternative you like can be used. A common approach is to heat the liquid until steaming rather than boiling, pour it over the product, and stir thoroughly so the cup turns out even. Using boiling-hot liquid is not necessary and can make the drink harder to sip.
Sweetener is optional. Chicory brings a natural bittersweet note, and cinnamon adds a soft sense of sweetness, so many people may not feel the need to add sugar. If you usually sweeten coffee substitutes, try the drink plain first, then add a little sweetener only if the bitterness feels too pronounced. There is no single “correct” preparation — the packaging instructions are the best starting point, and milk choice, liquid ratio and sweetness are personal preferences.