A window will open asking what you want to do with a file called ZoiperFreeInstaller.exe. Click 'Save File'.
2. Follow the Setup Wizard
When the download is done, click on the ZoiperFreeInstaller.exe file from the Mozilla Downloads window to open the Zoiper 2.0 Setup application.
(Alternatively, you could open it directly from the location you saved it which is typically your desktop.)
The Zoiper 2.0 Setup Wizard will appear and guide you through the rest of the installation.
3. Start Zoiper 2.0
After the installation has completed, you can open Zoiper 2.0 by clicking on the icon on your desktop or by click on the windows Start button -> All programs -> Attractel -> Zoiper -> Zoiper Free.
When zoiper is running an extra icon will be added to your tray icons, right clicking will provide you with some more options.