I am a 77 year old male and i want to have larger breasts naturally. what can i do to achieve this?

Do you really mean large breasts or you mean a muscular chest? Some men have big breasts with fat deposition if they are obese so you should not make your breasts bigger that way but exercise such as weight lifting can still give you bigger chest muscles, pectoral muscles, although it is limited at your age due to low testosterone.

Why do you want larger breasts? You want to look like a woman? There is no "natural" way to make a man's breasts bigger.