Hi Chris - you/your team need to read the Missions & Rules again, as these points are covered. However, it can be a bit confusing as a Rookie team!
All the Mission Models (game pieces) will be set up ready at the start of your match. Your team cannot touch or move any of the Mission Models outside of the Base area. Your robot can attempt any or all of the Missions in any order.
When the robot is in Base, the team can add/remove attachments to the robot - no problem. Once the robot is outside of Base, the team cannot touch the robot without incurring a penalty - this year, the Referee will remove one of the Levees each time they touch it. Therefore, if the robot returns to Base autonomously, there is no penalty.
Chris