Excel Numeric Entry Work and word document entries in a series order in a new folder

Column A includes existing members, and column B includes new members that have been referred by members from column A. Column A has many duplicated names. I basically need to find all duplicated members in column A and put all the names they referred next to them in column B, C, D, E. I can explain more through live chat. and you only need a laptop and smartphone to complete this task