MWGrinpool Payout

Hey guys,
I am just stuck a little bit with the payout on MWGrinpool.
I am not sure how to set the manual payout.
When I click on manual Online Wallet/Port, there is already som generated address that can´t be changed. It´s actually my address of wallet? I am not sure, because I didn´t set anything yet and in the Payment info the address is n/a. I would be glad if you can guide me through this. Thanks.