what do you use to shade?

ok, watch this or read below so you just start off with your base color, made the shape you want on the blank grid canvas select another color and click the color palette thingy at the bottom right of the defaults and then there's the hue and opacity in the menu make the color to pure black drag the slider of the opacity one and if you do, it switches the HEX color code into the RGBA menu slide it to your preferred opacity that it says in the "A" of "RGBA". I think 0.01-0.1 opacity should be good. the lower the opacity the better switch the tool you're using to the weird pen tool below the fill bucket select some pen size visualize where your light source is and shade at the other side where there is less light