Before you start reading how it works, make sure you have the Mac OS X 10.10 or newer. The plugin doesn't work with an older version.
Also, the plugin is compatible only with some older versions of Skype (7.49.274 and 188.8.131.520) which can be downloaded from this site: https://skype.en.uptodown.com/mac/old
If you meet the 2 requirements stated above, go to your SkyPrivate account in https://accounts.skyprivate.com/ and click on "Download Skype Plugin";
Click on the Apple Mac logo and the download will start immediately.
Click on "Open" to accept the installation setup
After the installation is complete, select to "Allow this application to use Skype" and then click on the OK button.
You should see the plugin running in the menu bar. Make sure that you're also logged into it with your SkyPrivate username as shown in the example.
When a member tries to call you, the plugin will show if he is or not a SkyPrivate member and if he is or not able to pay.
Example of a caller who is registered on SkyPrivate and who has money in his account:
If your SkyPrivate account is not verified yet, the member will need to approve the payment separately. This is what the pop-up message will show:
After the payment was approved, you will start to charge him every minute as shown below: