You need to put a link to a page on your website with a privacy policy. It can be as short or as long as you want. In the past there has been checks that Facebook has automatically performed on the page to ensure it actually is some sort of privacy policy page, but I believe those checks are gone. You likely can put your home page URL, but if some sort of error is thrown, create a URL on your site with some sort of Privacy Policy and use that.
Finally, if you use a search engine and look for "Privacy Policy Generators", there are tools out there that let you select a few options for how you protect and use information from users and policy text is generated that you could use. It's your policy, so I'd still recommend reading over it, but it's an option to get something up quickly.
I hope that helps,
Alex
Privacy Policy URL on FB to enable "In Development"
