Free Paid Programs

I have been searching for months.  Not what to sell, how to sell, or how to get traffic to my website.  I am looking for the simplest of all things. 

I can place a book or software on my site.  I can add a link to it.  But, where does the link take the customer?  I assume it takes them to PayPal.  I would hope that PayPal would give me the link.

Now...  when someone wants to buy something, they click on a button, it takes them to PayPal, they pay for it...  where do they go from there?  How do they actually get the product?  I can't send it to them via email because I am not on 24 hours a day, contrary to what my family says.

So, I am assuming there is a place they can go to download the product.  If it is on my site, what stops someone from downloading it without paying?  How does a download work?  If one person downloads it, is that a copy they are downloading?  Will the next person be able to download it?

All the gurus give all kinds of advice on marketing, list building, traffic generating, but not one of them can or will answer the basic of all questions.

Keep it real...

Pam