Just use a measuring cup for the 3 to 1 ratio. So like if you wanted to make a cup, 3/4's should be grains, 1/4 should be legumes. What it means is you get every essential amino acid, the ones the body cannot make for itself. Grains have some but not all, legumes have the ones grains done have and vice versa.
Glad you're enjoying the forum! It IS a good idea to read everyone's posts and not just your own, you never know what might help you out. :)