If you win a lot, it will show up on your profile in the Won Items page. You will also receive an email notification.
You can access your won items by hovering/clicking the Account drop-down and selecting "Won Items".
Once there, you will see all of the items that you have won. You also have the option to contact the auction house and to pay your invoice (if the invoice is sent via LiveAuctioneers).
All payment and shipping arrangements are made directly with the auction house, so if you do not see the answer to your question in the auction's terms and conditions it is recommended to contact them directly. Auction houses typically email you an invoice with payment instructions within 24-48 hours of the end of the auction