Click on the middle numbers in order to turn them on/off (maroon/green). The rows must be factors of the the number on the sides, and the columns must be factors of the number on the top and bottom. When the puzzle is completed you will get a burst of confetti, and can press the flag to play again!
This took me about a week to get the base game coded. Plans for the future: Hints Saving and Loading Different sizes of grids Addition mode maybe?