inputting data

I love this and I know that I can get it to do what I need it to, I just can't figure out how!
I'm trying to input data into a form.
I want to be able to be able to import a spread sheet with item numbers, descriptions and distributors weekly. How do I write a script so that when I import data the distributor names are recognized and if the name is repeated a new record isn't formed same for if that item is already associated with that distributor.
I've been at this for days and I'm not getting scripting.