Along the top-left of the LightZone browser window is a toolbar containing the set of photo buttons shown below.
The Edit button is equivalent to Browser > Edit.
The Open button is equivalent to File > Open.
The Print button is equivalent to File > Print.
The Styles button allows you to apply a style to the photos of the currently selected thumbnails. More on styles...
The Send button is equivalent to File > Send.
The Convert button is equivalent to File > Convert.