dissolve in cold water, ONLY THEN add hot water. The rationale behind it is that aromatics evaporate too quickly when the instant powder is infused with too/boiling hot water.
I only use it to make Dalgona coffee. Basically a tablespoon of crystals, tablespoon of sugar, tablespoon of boiling water. Whip it until its a really thick foam, almost like shaving cream, then you put it over some milk, ideally also lightly sweetened as the foam ends up really bitter without a shitton of sugar which I don't prefer to use.