Follow the steps below to calculate and visualize the band structure of silicon. We will use the extended Hückel method for speed and accuracy (!), but the change required to use DFT instead will be pointed out.

1. Start VNL.
2. Open the Database tool by clicking its icon on the main toolbar.
3. In the Database window, type "silicon" in the filter field at the top, and select Si in the list.
   
4. Click the "Send to" icon in the lower right-hand corner of the window, and select Script Generator.
5. Double-click "New Calculator" in the left-hand column.
6. Double-click "Analysis" and select "Bandstructure" from the menu that appears.
7. Click the "..." button next to "Default output file" and define a suitable location and name (for instance "si_minitutorial.nc") of the NetCDF file in which the results will be saved.
   
8. Double-click the "New Calculator" block in the right-hand column to define the parameters for the quantum-chemical method.
9. Switch calculator to "Extended Hückel" (or leave it at DFT if you so prefer), and specify a k-point sampling of nA=nB=nC=5.
   
10. If you use the Extended Hückel, you must also change the basis set to Cerda.Silicon to get a proper description of the band gap.
    
11. Click OK to save the changes.
12. Double-click the "Bandstructure" block; we will not change anything, but you can see how the path in the face-centered cubic Brillouin zone between the symmetry points G (Gamma), X, W, L, K, and so on, is set up. Click OK.
    
13. Save the script (menu File>Save) for later reference.
    If you are interested in inspecting the actual Python script, you can now send the scipt, again using the "Send to" icon, to the Editor. Note that this will minimize the Script Generator window.
14. To run the script, click the "Send to" icon in the Script Generator, and send the script to the Job Manager. When the Job Manager opens up, click the button "Process Queue" to run the script.
15. When the script has finished (it should only take a few seconds), go back to the main VNL window, and navigate to the directory where you chose to save the NetCDF file. Select the created NetCDF file, and the upper right panel will display a list of the objects contained in the file.
16. Select the Bandstructure, and from the list of actions in the lower right panel click "Show".
17. In the band structure plot that opens up you can right-click and select "Anti-aliasing" to improve the quality. Zoom in with the mouse or press Ctrl-R to zoom out. You can also right-click the plot and choose "Export image" to save the band structure plot in a variety of bitmap image formats.