Page 15 has Bobbin winding instructions.
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Download an image (png or jpg format) and open it in Adobe Photoshop
You need to limit the number of colors in the image.
Image -> Adjustments -> Posterize
Check the preview box, so that it will show you the effect of changing it to 4 levels.
The largest dimension should be no bigger than 4" for most student work. Talk to a teacher about the exact size if you're uncertain.
Image -> Image Size
If it's possible to remove any white space around your image, do so now.