Download a copy of the PDF textbook. The amount of time this takes will depend on the file size or length of the book. Make sure that you're downloading a legal copy of the book to avoid copyright infringement.
Open the PDF textbook file on your computer or electronic reader. If you're using a computer, you might need to first install a PDF reader, such as Adobe Reader.
Scroll through the pages of the document until you find what you're looking for. This action is similar to turning the pages of a book.
Explore your PDF reader's features to learn how you can best use your textbook. For instance, you might be able to make notes on a page, bookmark pages and highlight sections of text.