Yellow box around the object vs gray box around the object and how to manipulate them correctly?

Ladies and Gentlemen,
I am building a model of a VNA forklift.
I have created a 3D model of the major components thereof and replaced the appropriate components of the Transporter object with those new 3Ds.
As a result both yellow and gray boxes of the animation creator do not reflect the dimensions correctly and the vehicle seemed to have incorrect center of rotation/motion. How do I manipulate those two boxes correctly?

The boxes I am referring to are on those two photos:







Thank you!
Vadim

In the Animation Creator you should shrink the individual components down to fit within the gray box. Then press the "Save Base Positions" button. This will save all the "base" positions and sizes of the sub-components so they scale based on that base position. If you want to then change the base positions to be bigger, then in the regular 3D view, increase the total size of the object by holding Alt down and dragging one of its sizers. Then go back into the Animation Creator and hit "Save Base Positions" again. That won't change anything you see, but it will re-save the "base" point based on the new larger size.