VIEWSONIC VS13394 - Manual (Page 44)

Adding Bookmarks
You can add a bookmark on the current
page of the book. The top-left corner of
the page will be marked by to indicate that it is
bookmarked
Press button or by selecting Bookmark in Option
menu when you read a book to add a bookmark to
the current page. Your bookmarks will be stored in My
Bookmarks for further reference.