Step 1. Starting MinLab
Type "minlab" at a unix shell command prompt. A small menu window should pop up.

The MinLab main menu

Step 2. Loading a MinLab surface specification file
On the menu, choose "File | Open MinLab File". A file panel should pop up.
Click the "Library" button in the panel.

The Open File panel (File | Open MinLab File)

Double-click on "catenoid.min" in the right window of the panel.
The file-read panel will close.

Step 3. Computing the surface
On the menu, choose "Controls | Compute Surface". The viewer window will appear with showing the the catenoid, a simple minimal surface.

The iSight viewer window

Drag the mouse in the viewer window to move the surface.