To add a donate button to your charitable organization's Facebook Page:

  1. Go to your charity's Page (you must be a Page admin).
  2. Verify that you are registerd as a "nonprofit organization" in the "about" tab.
  3. Click Add a button. If you've already added a button, click the Edit button and select Edit Button to change the text.
  4. Select Shop with you or make a donation > Donate and then click Next.
  5. Select r Website Link and add your simplyk donation page url.

(this article was originally written on the "facebook" help page)