This grass will benefit from some cold, moist stratification. Either sow it outdoors where you'd like it to grow no later than March, or mix the seed with moist sand or potting soil and store in the refrigerator for 3 to 6 weeks before sowing. If stratification is not an option, we've had luck soaking the seed in water overnight before sowing.
An ounce of river oats should cover about 500 square feet.