Excel Formulas getting information from 1 workbook to another
 

I have a huge customer base, 4 columns, 1st column has the number of the
customers, sceond one has name, third one has location. Because my program
is so big that I cant have many on one file so I need to put my customers on
a sepearate workbook, when I insert the customer number on the main workbook
then I want it to access the customer number in column one, and the name in
column two plus the location in column three. I understand how to do those
formulas its just gettting it from one workbook to another. Thanks I
appreciate the help as always.