Some cheeses, like basic ones coagulated with acid need to be heated first to denature the whey proteins, so that the milk can coagulate. It's just the type of cheese it is.
If you want easy cheeses that are not aged and not heated, you're somewhat limited to making fresh cheeses like chevre that's coagulated by the lactic acid bacteria produce.
Use about 1/2 cup water per tablet to make sure it's dissolved thoroughly. Not sure what you mean by the 2 T question. Which recipe?
If you want easy and not heated, try making fresh cheese curds, cottage cheese, or chevre.