|As per the Help files, the syntax of VLOOKUP is:|
VLOOKUP(lookup_value, table_array, col_index_num, range_lookup)
Your lookup_value is A7
Your table_array is Sheet2!$A$!:$C$786
Your col_index_num is 2 for Column B and 3 for Column C
Your range_lookup is FALSE or 0, since you are looking for an exact match
Therefore A8 should contain:
=VLOOKUP(A7, Sheet2!$A$1:$C$786, 2, 0)
This will "look up" the value you put in A7 in the list of codes in the first column of the table_array (Sheet2!A1:C786) and return the value from the 2nd column of that table, which would be Sheet2!B1:B786.
To pull values from Column C, use =VLOOKUP(A7, Sheet2!$A$1:$C$786, 3, 0)
Note: The col_index_num is 2 for Column B and 3 for Column C only because they are the 2nd and 3rd columns of your table_array, not because they are the 2nd and 3rd column of the spreadsheet.
For example, if your table_array was G5:J47, a col_index_num of 2 would refer to Column H, the 2nd column of the table_array. Column J would have a col_index_num of 4.