Reading select optiosn and parameters ..confusion in Function Modules

Hello all

can any one tell me the exact use of the following fn modules

F4IF_FIELD_VALUE_REQUEST

DYNP_VALUES_READ

DYNP_VALUES_UPDATE

<b>RS_REFRESH_FROM_SELECTOPTIONS</b>

To be more specific i called the FM 'RS_REFRESH_FROM_SELECTOPTIONS 'but i dun understand how to use the table parameter in this afer wards

for EX .

DATA : select-options s1 for sfliht-carrd no intervals.

DATA : ITAB1 LIKE RSPARAMS OCCURS 0 WITH HEADER LINE.

CALL FUNCTION 'RS_REFRESH_FROM_SELECTOPTIONS'

EXPORTING

CURR_REPORT = PROGNAME

TABLES

SELECTION_TABLE = ITAB1

but now what to do ahead ?how can i access the select options from this table ITAB1..whhat is the use of calling this function. ?

Thanks in advance

Nilesh