One problem with that tutorial is that it is for Studio. Companion allows you to delete any step. On the left is a list of each action. You can select the step you want to remove and click the "Remove" button. One thing to remember, with SCI0, the background PICs are vector graphics. In other words, it is not based on collection of different colored pixels (raster), but a series of "commands" to draw lines. While it can specify individual pixels, it is mostly lines and fills. Deleting any one of these commands removes that action, thus "erasing" it. You are limited removing the entire line or fill. You cannot erase half of a line, but you can delete it and redo the way you want. You will probably want to insert the replacement at the same point, or you might have a fill command placed before your intended fill area is defined. In other words, if you draw a triangle and fill it, then redo one of the lines, if the redone line is placed after the fill, the fill will spill out beyond the intended triangle.
Also, the pallet may be limited to 16 colors, there are effectively more with dithering. Dithering was invented by Ken Williams, the founder of Sierra, is where the fill is alternating colors that give the impression of an in between color. Red checkered with white was often used simulate flesh tones or green with black to give the impression of a dark green. Done properly, it can have a very pleasing effect.
