How admin can view, choose winners and delete bids?
When user bid on products, otherside admin arrived bid to wordpress dashboard.For checking all bids admin needs to go Auctions -> Bids.There admin can see all bids of user's.Another way for checking bid for that go to Products -> edit product.There admin can see new table created "Bid History".
If admin wants to delete bid then Go to Auctions -> Bids as mention above.There are list of bids available, from there delete bid.
Admin wants to choose winner then go to Auctions and choose winner from list.When admin choose winner at that time user get notification for payment of product and user do further process.
So, in this way plugin works for bidding process.