I need to add a mileage calculation box to an existing form created by someone other than me. Please help, I am new to javascripting.

I have the book 'Creating Dynamic Forms with Adobe LiveCycle Designer, but none of the javascript or formcalc script is working. Can someone tell me step-by-step how to go about adding this to the existing dynamic form?

I added a small table on the existing subform, with the other 2 tables already in the form. This looked like a straight forward project. But, I have not any experience in java script other than googling for script and adding it to Adobe Acrobat fillable forms. So, I am sure I am going at this wrong.

Respectfully