How do I check and manipulate the data from a flat before loading them to teradata database?

As the topic, how do I manipulate the data from the flat file before loading them onto teradata database using BTEQ script.... I'm unsure which part should the manipulation be written onto the bteq script....

                  USING
 ------------------------------------------------------
                 INSERT INTO
 ------------------------------------------------------
                  Values
  In my opinion, data manipulation should be done here
  ------------------------------------------------------

  Table Name : Jerry
    A
  -------
  | 5   |          
  | 6   |          
  | 7   |          
  -------

Values in the data file,
   00005|Jim
   0    |Apple
        |Loop

Condition:

The data is read from the data file. The row whose first column is 0 or NULL should not be loaded, also the leading 0 should be executed before loading into the table........

Guess:

VALUES 
(
 IF TRIM(LEADING '0' FROM :A) != NULL OR IF TRIM(LEADING '0' FROM :A) != 0
 THEN TRIM(LEADING '0' FROM :A)
,B
,C



 );