She measured the flax seeds as 4 TBS and she put them into a coffee grinder, when done it give about 1/2cup plus 2 TBS of ground flax powder.
Personally I just fill my coffee grinder until it covers the blades and it gives me the approximate amount.

It depends on the size of your container. I make mine in a 4 cup measuring plastic mug, and it poof over the top.