I love the format of the book.  There's a story about exploring an ancient Mayan Temple.  Since it's filled with bobby traps, they need the robot to release the mechanisms making it safe for them the enter.  The story is a fun excuse to create a series of different robots.  

I've been working with a First Lego League team and they have gotten good results creating robots with trial and error.  They build something, then see if it will do what they need it to do.  Once they get that program and robot working, then they try to get it to do something else.  Again it's trial and error until the second task is accomplished.  In the process, they've often changed the robot and now have to see if it will still do the first task.  It was a good method to for beginners, but definitely has short comings as the robots and tasks get more complex.

I wasn't sure how to introduce them to planning and designing before building.  

I like the way The Mayan Adventure lays out the steps to design a robot.  Their format starts with a description of what the robot should do.  Then has the reader create a list of tasks and any constraints (e.g. height or size).  The next steps use that information to design, build and program a robot that fits the description.  

The book takes you through the same process for 5 different robots that are needed to explore the Mayan Temple.  It's a good story that the kids would have fun with and hopefully, they will learn about structured design and programming.

Read more about LEGO NXT Mayan Adventure week.