Novice help-sort & paste

Can someone help a novice? I have a list with one column of numeric customer ID numbers which are somtimes duplicated in the list (different invoices to the same customer), and three columns with corresponding customerID number,customer name, and an alphanumeric ID from a different source. I want to find the corresponding numeric ID and paste the two adjoining columns (name and alphanumeric ID) next to the numeric ID in the first column. I'm trying to use VLOOKUP, but am missing something-or mabey I'm looking at this the wrong way. Help would be sincerely appreciated.

VLOOKUP will do the trick, but the rows with blank names and aplhanumeric IDs can't be part of the range in the second argument. So I would sort on column B, then make the second argument of the VLookUp the range with data in column B.

When finished, copy the whole table, and paste special, values, back to the same position to convert the VLokkUp formulae to values, then sort back on column A.

HTH

Art