The card does not describe mixing with hot drinks. According to the card, hydrolysed collagen is taken with food and drinks, and the daily portion is 2 measuring spoons (10 g); the powder is unflavoured. The card does not name the temperature of the drink or compatibility with coffee or tea.
General information (not a manufacturer's instruction): powders are usually stirred into a liquid until dissolved; the exact preparation method is on the packaging.