If you bought from our store, simply click on the "Download" button for the appropriate platform on our website's download page.
Once installed, if you haven't yet entered your licence, the software will run in trial mode. To unlock it, click the "Enter Licence..." button on the trial message, then enter your email address and the licence code you were sent via email after purchase. (If you have lost your license code, please use our Lost License Recovery page to have those details sent to you.)
If you bought from Apple's App Store, visit the "Purchased" area of the App Store app and download from there.