Single input by user automates other fields

I'm sure this has been addressed before, but I have searched, and I don't seem to find the answer to my specific question. So here goes.

I am creating a PDF form that I want to auto populate about 15 other text fields (fields are all different) on the form based on the user entering an id in another field. For example, the user will enter "9999" in field 1, and it will then populate the rest:

Field 1 = 9999

Field 2 = some info

Field 3 = diff info

Field 4 = more diff info

etc.

Field 15 = yet more diff info

Option 1: The data in those other fields (fields 2-15) is in an excel file. So, do I merge the data, where field 1 acts as the trigger? If so, how do I do?

Option 2: Or should I just import a separate .txt file and create separate pdf forms for each user?  This seems to be the most easy, but also less automated for the user. Less impressive.

Option 3: Should I just create the script specific to each user in the main PDF and then save a separate pdf for each user? Where does it go? In field 1 or in each of the fields 2 - 15? What is the scripting for that?

Please be very specific as I am very new to using scripts.

Thank you very much for your help.