To print a range of entries from a book or a commentary, first make the book or commentary you want printed active by clicking on its tab in the Book or Commentary panel. Then select the appropriate option from the File menu: Print Range of Comments prints a range of verse commentary text from the active commentary, and Print Range of Book Entries prints one or more entries from the active Book or Dictionary.
Usually, you will just want to print one entry. The best way to do this is to make the Book or Commentary entry you wish to print active in the Book or Commentary panel, and then select File > Print Book/Commentary Panel Text. This is especially handy for printing out a personal book module entry to be used as a Bible study handout.