The Senonics MAC application is not available yet on the Apple Store. Follow the instruction below.
Step 1: Download the application from here.
Senonics Mac Application Installer (.dmg)
Step 2: Double click and install it to the Desktop or somewhere convenient.
Step 3: The first time you try to open it your Mac will know it has come from the internet and it will warn you that it does not come from the Mac App Store.