There are two kinds of bids. A static bid means you place a bid yourself. If your bid is overbid you need to place a new bid again. This will continue as long as you are overbid and you would like to remain the highest bidder.
When using an automatic (‘Auto’) bid you indicate the maximum amount you want to pay for the lot. Each time your bid is overbid the auction system will automatically place a higher bid. This will continue until the maximum amount you have indicated has been reached. In case a static bid equals an automatic bid the latter will prevail. (automatic bid wins over static bid). If you want to end the automatic bid you need to place a static bid based on the next highest bid. Please note it is not possible to cancel an automatic nor static bid once you have confirmed.