Let’s say that three buyers were filling orders for shares of company ABC, with buy prices of £5, £5.30 and £5.60 respectively. Meanwhile, three sellers had submitted offers to sell their shares of ABC for £4.40, £4.70 and £5. In this case, an auctioneer would match the £5 buyer with the £5 seller and the trade would go through. This would set the current market price for that stock at £5.
Once this has happened, the buyers and sellers who put forward the other prices would readjust their values to trade at the price set by the auction at £5.