You can do many things with them. Most gals print them on sticker paper and then cut them out. If you happen to have a cutting machine then you can use that as well. Here is a video. https://youtu.be/KIIyXbWGdaM
Some use them as traceables and put them behind the page they want to color on. Here are some other ideas: https://youtu.be/mkXfr_-rouA