After you've purchased PDF2Word, you should receive an email with a link to download the software. Once you click on that link and save the program to your computer, you can run the installation process.
Run the installer.
Accept the License Agreement and click "Next"
A default destination install folder will be provided - you can change that folder by clicking on the "Change" button from the prompt. Click "Next".
Click "Install" and allow the installer to complete the process.
When you reach the "InstallShield Wizard Completed" dialog, you have the option to "Launch the program" immediately, or remove the checkmark from that option to just complete the installation without launching.
When you run PDF2Word for the first time, you'll be asked to activate.