The bid box is on the right side of item description page. The site will bid on your behalf, so set your real maximum bid. Your bid will only be raised if you are bid against by someone else. Remember, the first person who bids a certain amount will get the bid for that amount and bids will only be accepted at the bid increments: (If you set a max bid at $501, you will only be protected to $500, but someone can only out bid you by bidding the next bid increment, $525
Notice some auctions will have reserves, but most are No Reserve Auctions. Many sellers will not post auctions for premier items unless they are protected by a reserve. So if those items did not have reserves, you would not see them for sale. In the opinion of the seller, the reserves are reasonable in today’s antique market.
If you have met the RESERVE or the Auction has NO RESERVE, a bolded notice near the bid box will inform you of this.
Good luck and don't wait until the last minute.