Set the most you would pay, and the site bids for you, one step at a time.
Enter the highest amount you are willing to pay. It stays private. The site raises your bid only as far as it needs to keep you ahead, so you can win for less than your maximum.
If two people bid the same maximum, the earlier bid leads.
A bid that changes the price or the leader in the last 2 minutes moves the end to 2 minutes from that bid, up to 60 minutes past the original end. Last-second bids cannot decide an auction.
You may retract a bid for a stated reason, except in the final 12 hours of an auction. The price can fall when a bid is retracted.
Sellers cannot bid on their own items, and neither can accounts linked to them. Bidders appear under an alias that changes with each auction, so nobody sees who is bidding.