You may need more time if the weather is humid or cold. When dry, the plaster should feel hard and produce a ceramic sound when lightly tapped. Lift the casting by digging it out of the ground. To be safe, let it dry another 15 minutes or so, then carefully clean off the debris . To preserve the casting, spray it with lacquer or varathane.
Animals leave tremendous clues to their passage.
Your ability to notice these expands with the amount of time you spend in the woods. Stay alert and ask yourself questions. Tom Brown Jr. Brown operates a school that teaches tracking and wilderness survival, which I also highly recommend. You can use tracking skills year-round to improve your knowledge of the game animals and furbearers in your area. Knowledge like this is impossible to acquire without firsthand experience.