Press the Home button and select TouchWiz Home from the list, then choose "Always" .
You use this device for daily banking, social media, or any activity requiring modern security. Android 5.1.1 has known vulnerabilities. For daily use, it is smarter to keep a modern launcher on a newer OS. samsung touchwiz home lollipop 5.1 1 download
You cannot install the official TouchWiz launcher. The framework (TouchWiz resources) is missing. Your phone will bootloop. Instead, you need a "Port" — a third-party launcher that mimics the look: Press the Home button and select TouchWiz Home