Your real estate agent will be notified upon the win of your bid. Then there is a 48 hours window to get your payment in. There is a lot of paper work involved and it needs to be filed timely and properly.
If you win a bid on a HUD home you will need to finalize your inspections expeditiously (check your contract for the inspection period) and work with the bank to be sure you loan will fund by the closing date...your realtor should help you with this.
Make sure your financing is already approved and you have a down payment to give right away. After the bid comes in you usually only have a short window to complete the transaction or they will go on to the second person.
Your real estate agent will be notified immediatly upon acceptance of your bid. The agent will then have 48 hours to get the original documents along with your earnest money check to them in order to finalize the offer.