Please Help!! How do you make an ebook...

Hello Folks, sorry if this may sound like a "not so smart" question, but I just do not know and all the ebooks I have do not explain it. I am a complete novice.

Here's my problem. I have an pdf ebook all ready to go but I do not know the next process. I do know I need a website, a host but from there I am lost. I want ot sell though paydotcom.com.

The big question is how do you make an ebook downloable from your website. After a customer pays they need to be redirected to a download page/link and I do not know how to set things up correctly where the customer will get thier product.

I have been reading about FTP's but I am still confused.

Could someone please give me some guidance.

Thanks
kelle