The simplest way to plot data in SmileLab is to use the plotting interface. This is a front-end user panel in which you can import file data, specify some computing and plots, and access graphic settings.
The plotting interface
Editing a graph's settings
You can access plot settings thru the Graphs ▸ Edit settings menu, or using the contextual menu.
The graphic settings
To know what operations you can perform in a graph with the mouse, and how you can get contextual information when you drag the mouse, please consult this page:
Using the mouse in a graph
File saving formats
You can read a short description of the save menu of graphic windows:
Saving graphical documents