When you submit your information, you are taken to a download page.
At the top of the page there are two links for downloading the license (ST3 and before and ST4 and after).
Click on the appropriate link.
The download is a zip file.
Extract the contents of the zip file under your My Documents folder. Do not extract to the Desktop.
The zip file contains a SELicens.dat file and a text file. The SELicense.dat file is the license. The text file has directions describing how to apply the license. Follow the directions carefully and pay close attention to the folder name that the license is to be coppied into. Some put the license in the wrong folder and the software still will not run.