All the downloads are available here either free software or full-functional trial software.
You can download and evaluate full-functional trial version of the software during 14 days completely for free to make sure it suits your needs. Then you can purchase it here.
To download the software, just click appropriate "Download" link.
If your browser will ask you "Save or Open?", choose saving and specify desired location. When download will be completed, just run it from that location to install the software on your computer.
Also, you can download additional spell check dictionaries for many languages. Just click the next link and choose required files on opened page: http://www.addictive-software.com/dicts-extern.htm. Put downloaded files to the folder {Program Files}\AVELife\Common Files\Dictionaries.