Just use arrow keys to move. Not perfect. Discovered that Scratch has a size limit in pixels to the amount you can scale in percent. I wanted to scale 200%, but the checkerboard sprite only allowed 180% due to its size. UPDATE: Thanks to GameMan2's expert knowledge in Scratch, he let me know that if I scaled up a smaller object by 200%, then just switch costumes, it would work... and behold, it did!
@GameMan2 for letting me know about the scaling workaround.