To start the installation process, you must first download the Spinoco Application from the Apple App Store. Navigate to https://spinoco.com/en/for-existing-users and click the iOS download button to get started. 

Alternatively, you can go directly into the AppStore, and search for Spinoco:

To download the application, hit the "Get" button next to the Spinoco application name. 

The download will be completed in the background, and once it is ready, simply hit the "Open" button to start using Spinoco.

When you open the Spinoco application, you will be prompted with two dialogs asking you to confirm further permissions. Please select OK to allow Spinoco to access your Microphone. This is to enable you to make phone calls via the Spinoco application.

To receive calls successfully, it is also necessary to enable notifications for the Spinoco application. In the pop-up dialog, hit "Allow".

You're all done and ready to start using the app!