This is where you can (re)download the latest Mac or Windows versions of the software. Please note, there is no difference between this and the 'trial version' (the 'purchased version' is just the trial version but unlocked by the email/code)
If you purchased the Mac version via the Mac AppStore then things are a little different. The Mac AppStore version is a 'special download' and doesn't require any unlocking. You can redownload this via the Purchased section of the Mac AppStore app.