Click the squares on the grid to paint them, and if you hold down left-click it will keep painting as you drag your mouse along the squares. Choose Color Button - Type the number for the color, put a dash, type the numbers for what you want the saturation to be, put a dash, put the number for what you want the brightness to be, and finally put a dash and press enter (or press the check mark if you are on mobile.) The erase all is a little slow, but I didn't have any better ideas.
All credit goes to me and my dad. Please love, fave, and follow and if you don't do it because of this I hope you will reconsider when you play my 19 level platformer here: https://scratch.mit.edu/projects/426974717/ (you may have to copy paste)