After the download prompt appears, save the file and wait for it download successfully.
Next go to your downloads directory and find the Zoiper installer, then execute it.
A verification prompt will appear, click "Yes".
The Zoiper installer will start, click "Next" on the first screen of the Setup wizard.
Read the license agreement and click "Next" after accepting the agreement.
Select which components to be included.
Select the version you would want to install.
Select an installation directory (Best to keep the default one).
Choose a start menu folder.
Select which users should be able to use the new Zoiper installation.
The setup is now ready to begin the installation. Click "Next" to continue.
Wait while the Zoiper installation finishes.
The install wizard will inform you for the Zoiper Biz Plugins which should be already installed.
The installation is complete. Click "Finish" to launch Zoiper.
MacOS X Instructions