Badge 3 begins with the final part of the Engineering Design Process, sharing your design.
Now, that the girls have plans, designed, tested and improved their robot design it is time for them to share their final design with the troop through a presentation. They should take the time to create a presentation about their robot and about the program they created and the problem their robot is "solving".
Steps 3 through 5 is about learning about robotics and robotic teams. This is where I defer to my experience as a First Lego League coach. Our council has several Girl Scout Robotics teams that could be contacted to come give a demonstration during a troop meeting or that you might be able to Skype with. You can also check out the Jr First Robotics League (JrFLL) You Tube page for some videos on competitions. https://www.youtube.com/user/JrFLLGlobal
There is a great new program called Skype a Scientist that teachers can sign up and skype with an actual scientist. I would suggest signing up as a "teacher" and schedule a Skype Q&A with a robotic scientist for one of your troop meetings.Have the girls prepare some questions in advance of the Skype meeting.
Here are some virtual tours of Robotics Lab's you can investigate: