Most printed and electronic resources are protected by copyright restrictions. Make sure you have the right permission to copy or download any resource you plan to use.
Copyright restrictions are not just guidelines, they are law. You do not automatically have the right to copy or download books, articles, images, photos, diagrams, newspapers and magazines, videos, tables of data, etc.
The copyright agreement may give you limited rights, e.g. to copy a single chapter of a book, or use some information for non-commercial purposes.