How to setup the TestFit Add-in for Revit
Sign in and go to the license page at portal.testfit.io/license. Then scroll to the bottom, you should see The TestFit for Revit addin. Click on Download in the addin.
Once downloaded, run the .msi file and complete the steps when asked.
You've installed the TestFit Add-in for Revit. Once you open Revit, you'll see the TestFit tab on the top of the program. To import a TestFit site into Revit, continue with the Importing TestFit into Revit knowledge base article.
NOTE: Revit LT does not support add-ins, so the TestFit Add-in for Revit only works for regular Revit.