Create a new session in Pro Tools. Choose File - New Session from the main menu.
Create a new auxiliary track. Choose File - New Track from the main menu. A pop-up window will appear. This will be the track you will load Reason into.
From the pop-up window choose "aux" for track type and click OK. A new auxiliary track appears in the edit window.
Click the insert button inside the new auxiliary track. A pop-up menu will appear.
From the pop-up menu select "instrument." You will see a list of available instruments in the list. Choose "Reason" from the list. The Reason program will now begin to load. That's it. You are now ready to get to work using Reason in Pro Tools!