For people who like technical details, protein is made up of amino acids. Each amino acid molecule is like a bead, and many amino acids together make up the protein chain. There are many different amino acids, and all of the essential ones are found in plants.
And by all means, do not fret about protein grams or feel any need to count them. But if you are interested in the numbers, simply divide your body weight (in pounds) by three. That gives you an approximation of the number of grams of protein your body needs, plus a margin for safety. So, for example, for a person who weighs 120 pounds, 40 grams of protein is more than enough on a daily basis. Some experts believe that the actual amount of protein required is actually much less than this figure.
The bottom line is to have a healthful mix of vegetables, beans, whole grains and fruits, and protein takes care of itself.