Asexuality

I hope i don't offend anyone by posting this. I was just wondering if someone could explain asexuality better to me. When i looked it up i read "no sexual attraction toward anyone but they can still have sex." so I'm just a little confused i guess because I'm kind of a ditz. Could someone explain how you can have sex with people without feeling sexual attraction? I'd love to be more educated on the subject and i know I'm probably misunderstanding so please don't hate me!