ViewSonic VS13392 User Manual page 29

Zoom Button
Changes the size of the text while you are
reading
Bookmark Button
Quickly bookmark
Menu Button
Displays application and navigation choices that
are related to the screen you are viewing.
5-way Button
Selects an item or action when pressed. Moves
the on-screen highlight or cursor Up, Down, Left
or Right according to the corresponding button
press.
Volume Control
Move the 5-way controller to control the
headphone or speaker volume for audio books
and music.