Add oats, water (the lesser range will yield thicker, creamier milk, the higher range will yield thinner milk), salt, and any additional add-ins (optional) to a high-speed blender. Top with lid and cover with a towel to ensure it doesn't splash. Blend for about 30 seconds - 1 minute or until the mixture seems well combined. It doesn't have to be 100% pulverized. In fact, over-blending can make the oat milk slimy in texture.
Scoop out a small sample with a spoon to test flavor/sweetness. If it's not sweet enough, add more dates.
Pour the mixture over a large mixing bowl or pitcher covered with a very thin towel or a clean T-shirt. In my experience, it benefits from a double strain through a very fine towel to remove any oat remnants. A nut milk bag seemed to let too much residue through.
Transfer to a sealed container and refrigerate. Will keep in the refrigerator up to 5 days (sometimes more). Shake well and enjoy cold. DO NOT HEAT or it will thicken and become gelatinous in texture. It's delicious as is or added to granolas, smoothies, and baked goods!
*You can use steel-cut oats, but I found them to make the oat milk gummy and didn't enjoy their flavor as much. *Nutrition information is a rough estimate calculated with no additional add-ins, and the oat "pulp" nutritional content removed.