Download Page from Paypal Question

I have finally finished my first product. woo hoo.

I am waiting on the minisite template and promo tools before I put it up on clickbank.

I thought I would put it up on my blog and offer my readers a special price until I get it up on clickbank. Am just going to write a page on my blog so it will show up in the nav bar for now.

This is the first time I have done this and totally don't understand how to get them to the pdf in a secure fashion.

Can I just send them to the pdf url on my server in the successful payment url in paypal?

I thought I would set up a thank you page on my blog, but what keeps everyone else from finding and downloading the book?

I thought about password protecting the post, but then how do I get them the password?

I don't know how to build a regular html thank you page, or I would do that.

I was thinking I would just email them the pdf when I got their payment notice from paypal. but that seems a little lame. When I buy an ebook I want it right NOW.

Any suggestions, written for a 10 year old, would be greatly appreciated from a newbie product owner.

I have already heard, just set up a download page. (that's the part I don't get)

Thanks

Jackie