In order to run multiple scenarios in a sequence, you need to use "Play Script" action. This feature allows you to nest an unlimited number of scenarios.
In your main scenario, add as many "Play Script" action as you need to the scenario, specify which scripts will play and in what order. When you run your scenario, ScenarioBuilder will play the scenario including all the sub-scenarios in order.
Note: You can also add scripts to the scenario by using "Project Scripts" window.
Here is an example: