You are not allowed to copy it, or sell copies of it

Under fair-use laws (which vary country to country), you can usually copy a small portion of the work for non-profit educational use

https://en.wikipedia.org/wiki/Fair_use

The first line of wikipedia: "Copyright is the exclusive right, given to the creator of a creative work, to reproduce the work"

You probably won't be in trouble until you start trying to distribute your copies, but the prohibited thing is copying. Hence the term copy-right.