After you add a scenario and once you've named it, select "set scenario details" i believe its the touch pad button on the controller, a menu shall appear with the off the rails option and just check the box and confirm.
One question I had on this, is there an option to set what weather you want for your scenario? I just can’t find that setting keep starting my scenario in heavy rain and can’t see a thing lol
Ah I worked it out. spawn on foot with the weather you want on the route that has your scenario. Then quit to main menu got to tools, launch your scenario and the weather is as you left it quick tip there DTG Protagonist if anyone wants to change their scenario weather. Wasn’t sure if there was another way