Newbie ? Please Help!

I'm a little new at this and need some help. My assignment is to modify the following function and do the following steps:
1.If ab_Table.a_col = xy_Table.a_col, then dosomething.
??How do I populate xy_Table
??How does ab_Table get populated in the code below
??How do I compare the ab_Table.a_col to xy_Table.a_col to see if they match
??Where should the code go in the function

/*This is what already exists, I need to know where to put my code.*/
tbl_rc_ab_Table Number :=0

TYPE ab_Table_rectab IS TABLE OF ab_Table %ROWTYPE
INDEX BY BINARY INTEGER

tbl_ab_Table_rectab ab_Table_rectab;

FUNCTION fCreate(p_arg IN OUT...)
n NUMBER :=0
IF tbl_ab_Table_rectab.COUNT > 0 THEN
FOR n in 1..tbl_ab_Table_rectab.COUNT LOOP
IF tbl_ab_Table_rectab.cola = p_arg THEN
tbl_ab_Table_rectab.colb :=1
END IF;
END LOOP;
tbl_rc_ab_Table = tbl_ab_Table_rectab.COUNT + 1;
tbl_ab_Table_rectab(tbl_rc_ab_Table).col_c :=0
END IF:Answers to your questions:
Both #1 and #2 - populate a physical table with the INSERT statement.
#3 - Use the equivalence operator to test variables of same type.
#4 - Well, the "record group" you declare is only initialized (but no
values are being populated in it), the arg val ("p_arg) is of both IN OUT
(only IN is needed) and all this loop is doing right now is making
"colb" equal to a value of 1 if "cola" equals the "p_arg".

First, I think you'll need to place values into this RG (using a Cursor
from the table). Once the RG has values, now you'll be able to
get something out of it with your FOR loop.