The stepwedge is essentially a negative with predetermined densities in equal increments. You can get them here:

http://www.stouffer.net/Photo.htm

The version I have is the TPC4x5-31

If I was to buy a new one I would get the TPC-4x5-41. It would be nice to have 1/6th step increments.

My method for calibrating starts with a calibrated film exposure and developing plan. My target density for zone IV is 1.20. This is step 12 on my wedge. The goal is to calibrate the analyser so step 13 is paper white and step 12 is just showing density. After making several contact prints to find the correct exposure for this, I note the difference in exposure between suggested and reality and use this to input the correct exposure compensation. This is done for every grade and half grade.

The second step is to setup the contrast. This is done by counting the number of steps on the stepwedge. Convert these steps to stops. Each stop is worth 30 iso units. Add it all up and this is your contrast range for that paper.