The previous owner had to delete their account so the Link Essential would be available for you to install.
As a result, you will need to install the Link Essential from the Somfy Protect app.
Once you have created your account, you will start by installing the Link Essantial. The app will take you through the process step by step.
The equipment should already be in place. To link the equipment, without the tab, simply reestablish electrical contact with the battery. To do that, remove the batteries, then replace them, taking care to place the positive and negative ends appropriately. Note: If the system has been out of service for a period of weeks, the batteries may be depleted and need to be changed
Link has not been uninstalled
In that case, you'll need to contact the previous owner so they can cancel it in their account
Menu > My device > Link Essential > Delete
Then, you will be able to follow the instructions provided above.