You would simply use them as an egg white replacement. So 10 large egg whites for example has between 150-175 cals & 34-38g of protein. Just eat according to your diet. I'm sure you could add them into shakes as well if you are asking for Ideas on "how" to consume them.
Quality egg white powder is expensive if you are trying to replace a dozen or 2 eggs a day. When I was competitive as a bodybuilder, what I liked or didn't like didn't matter. I ate what I needed. If I happened to like it, so much the better.