Looking for records with repeated data

You can use a query instead using locate, and step in the query for your
calculations.
    <<<< L R G M >>>> ? ???? ...
    About the Locate Method
    I have been using the LOCATE method to find out records in my DB tables.
All is OK when I use it with Customer_Number key field (it has just one
instanace), but others like First_Name or Last_Name can have repeated values
in my long Customer.DB table. Although, I only can get the first of them. To
sum it up, I want to create a searching routine loop usefull to keep in an
ARRAY as many as repeated data I could find in the chosen FIELD. Finally,
what is a practical way to show these selected data to pick up the record I
really want to see.
    Biginner requesting help.