Blend at 1 to 4 ratio. Ex: 1 cup almonds, 4 cups water. Strain through nutbag or cheesecloth. Save pulp for recipes (Google will help)
Some people drink the milk as is but to me, but it tastes even more amazing if you cook it on a stove just until it starts to boil and immediately turn off heat. Add a tablespoon sugar.
Cashews: same but don't need to boil. These don't strain as well so some people prefer using high speed blender and not strain but I didn't care for it that way. I haven't made oat milk that I'm happy with so no advice on that