Please note that the Ledger Manager is for advanced users only, as the app is not totally user-friendly and may have some burdensome functions - which don't undermine the integrity of your coins.
APPLICATIONS MANAGER FOR NANO S AND BLUE
Ledger Manager is like a free app store, from where you can make updates, install and uninstall applications on the Nano S and the Blue. It doesn't manage your coins or launch your accounts applications.
First, install the Ledger Manager (requires Chrome browser or Chromium), and launch it
Then connect your Nano S or your Blue, enter your PIN, and stay on the dashboard. For each action made with the Ledger Manager, a confirmation will be required on your device as a signature.
INSTALLATION OF THE APPLICATIONS
UPDATE OF THE APPLICATIONS
To update your applications, you need to uninstall the application, and reinstall the new version.
You can update the firmware of your Nano S from this Ledger Manager by following this tutorial.
The "Unable to install app" error message on your Ledger manager is displayed for several issues: