Here is the tutorial.
First of all make a spur gear from the last tutorial on spur gear. Here is the tutorial http://grabcad.com/questions/tutorial-creating-spur-gear-in-solidworks
Change the extrusion height and make it thicker.
Choose flex type - Twisting and select the gear body as flex input.
Enter the triad angle for x axis as 90degree.
Enter flex angle(Helix angle) as 20degree. Click OK.
We have the Helical gear created.