I do not understand some parameters for integration of payment process

hi, please i am dealing with a payment processing for the first time, and there are some parameters i do not understand, please can any one refer me to a document or samples on the parameters so as to be able to integrate the code well.thanks

the parameters and their description on the payment process manual are below

gtpay_tranx_noti_url Optional

The URL to which GTPay should send transaction status report to on completion of transaction. If not specified, merchant’s value in GTPay database will be used. If merchant has no value in GTPay database for this parameter, and the parameter is not included in the transaction request, GTPay will simply show transaction status report to customer, and not redirect back to merchant’s site.

gtpay_gway_name Optional

If specified, then customer cannot choose what gateway to use for the transaction. Accepted values are “webpay” or “migs” (Mastercard International Gateway) only.

gtpay_gway_first Optional

If GTPay should take customer directly from merchant’s page to the gateway to effect the debit/credit. If not specified, customer will be shown GTPay’s own first page, from where he/she will click Continue to go to the gateway.

NOTE: If specified, then gtpay_gway_name must be specified.

gtpay_echo_data Optional

Merchant can store in this parameter any data that it needs returned back at transaction completion.

sample of their form is below

<html>

<body onload=“document.submit2gtpay_form.submit()”>
<form name=“submit2gtpay_form” action=“https://ibank.gtbank.com/GTPay/Tranx.aspx” target=“_self”>
<input type=“hidden” name=“gtpay_mert_id” value=“17” />
<input type=“hidden” name=“gtpay_tranx_id” value=“” />
<input type=“hidden” name=“gtpay_tranx_amt” value=“5000” />
<input type=“hidden” name=“gtpay_tranx_curr” value=“566” />
<input type=“hidden” name=“gtpay_cust_id” value=“458742” />
<input type=“hidden” name=“gtpay_cust_name” value=“Test Customer” />
<input type=“hidden” name=“gtpay_tranx_memo” value=“Mobow” />
<input type=“hidden” name=“gtpay_no_show_gtbank” value=“yes” />
<input type=“hidden” name=“gtpay_echo_data” value=“TEST” />
<input type=“hidden” name=“gtpay_gway_name” value=“” />
<input type=“hidden” name=“gtpay_tranx_noti_url” value=“Put your response url here” />
<input type=“submit” value=“Pay Via GTPay” name=“btnSubmit”/>
<input type=“hidden” name=“gtpay_echo_data” value=“”>
</form>
</body>
</html>