If you want to grow your own pomato plant, you can find instructions here: https://plantinstructions.com/vegetables/what-is-a-pomato-plant-and-how-to-grow-it/

(last accessed 16.07.2021)

You can read more about the science behind grafting here: https://blogs.scientificamerican.com/brainwaves/the-science-of-pomato-plants-and-fruit-salad-trees/

(last accessed 16.07.2021)