I don't know exactly to what you are referring, but if it is soy flakes as meat sub, then, no, you'd not normally put it in cereals. (also referred to as TVP, TSP, Soy Curls, etc.)
I'd not recommend them for consumption, myself, but, if you are going to eat them, you should soak them in a "meaty" broth like a vegan "chicken" or vegan "beef" broth (use powders, soy sauce, or, better, use marmite) to rehydrate them. Then cook them as for meat. Flakes would be best as a ground "beef" sub, so burgers, pasta sauce, etc.
If you are referring to a soy flakes cereal, then, I suppose you could toast it, but it's already toasted and that would just add more insult (acrylamides) to the injury (its non-nutritous status).