Help! How do I change this?

[bugleman]

What do I look for in the php codes to find out how to make my checkout end up on the your order was a success page? Right now it's going to the account sign in page once the person pays for an order.

 

I'm using the merchant account paymenow for checkout. But it's all php codes the same as any of the other checkouts and if someone could direct me to where to look in the codes so I could change this I would be so happy! I don't know php.

 

If a payment doesn't go to the success checkout page then it doesn't go to your oders or inventory right? Reason I'm asking is since the checkout is going to the account page nothing is showing in my orders.

 

HELP!!!