Book Signings????!!!!?

ok so Corrie's Kym Marsh (Michelle Connor) is doing a book signing at the Trafford Centre on the 2nd July but my mum's got me a bit confused, I'm guessing that Kym will only be there at a certain time? and do you buy the book before the book signing and take it to her for her to sign it or would she have like a pile of books and just sign one for you? I know... I sound really stupid lol! Any answers will be great thanks :) xx