If they sent you grains that were frozen, you will need to make 2 or 3 batches for them to reactivate.
1 tablespoon of grains put in one cup of milk (2 deciliters) and keep for 24 hours.
Mine smelled bad two but after one batch it was good.
Im lucky enough to get really good organic milk from the farm and my grains love it. From one tablespooon, in a month i have like 15 tablespoons of grain. Already gave some to my friends to make for themselves.
So quality of milk is important.