The WP Get bookmark range command returns a text range object (rangeObj) containing the range for the bookmark with the specified bkName in wpDoc.
If the bkName bookmark does not exist in wpDoc, an empty rangeObj object is returned.
You want to show the range of the "MyBookmark" bookmark in your document:
C_OBJECT($wpRange)
$wpRange:=WP Get bookmark range(WParea;"MyBookmark")
WP SELECT(WParea;$wpRange)