Click this, then select 'Your devices and content', which was in the bottom-left for us. In the US, to the top-right of the main Amazon screen should be an option saying 'Account and Lists'. Just note, the following steps are slightly different in different regions' versions of Amazon - we'll talk you through the US and UK guide, but if you're in another country, you might have to hunt around for options a little more. You'll need to head over to the Amazon website and sign in first. You'll need to look up yours, as you're not told when you set up your Kindle, but it's little hassle. If that last clause makes no sense, don't worry - not many people know, but your Kindle has its own bespoke email address, using which you can send files to it.
To get a PDF on a Kindle, you're going to need to know your Kindle's email address.
