User guide PDF updates (#616)

Add link to download PDF on "Using SimpleReport" landing

_pages/using-simplereport/index.md

@@ -13,4 +13,4 @@ Once you’ve set up SimpleReport, you can begin using it in your daily work.
 
 Use the menu on the left to skip to a particular section, or start with [selecting your testing facility]({% link _pages/using-simplereport/select-your-testing-facility.md %}).
 
-You can also see [what’s new on SimpleReport](https://www.simplereport.gov/using-simplereport/whats-new/).
+You can also [download a PDF version of this guide](https://www.simplereport.gov/assets/resources/SimpleReport-user-guide.pdf).