There are two different ways to add Stops to your trip:
1. "Create Your Trip" Stops
When you first create a trip, the initial prompt asks the user to input your desired stops (including starting and ending stop) as well as any other known stops, in sequential order. These stops will be part of your trip (until you change or delete them).
Once you have pressed "Create My Trip!" you will see all your stops plus any automatically-generated GenieStops when your own stops are farther apart than your daily specified driving distance under Route Options).
2. "Add or Remove Stops" (after a trip has been created)
At the top of the Trip Planner list of stops, click on the button that says "Add or Remove Stops." Then add any new stops in the location you want them to appear. Notice that the automatically-generated GenieStops do not appear in this screen. GenieStops are not considered mandatory until you have either selected a campground for a GenieStop or locked it (by clicking the small lock icon next to the GenieStop name).
The new route will likely change, however, previous stops that you entered and any locked GenieStops will remain on your route along with any newly added stops. The Trip Planner may create new GenieStops to the newly added section of the route.