There is no way to install ShareIt app in Samsung Z Series phones as those phones are not working on Android Operating System. But by following below steps, you can install this or any android app in your phone.
→After downloading these files, Open system/privapp folder in your file manager and copy there 2nd, 3rd, 4th and 6th app from the downloaded list.
→Then copy and past google play servise app inside sustem/framework directory and copy last app downloadProviderUi inside system/app folder.
→After move all required applications, you have to delete acl vending from system/pivapp direcotyr before move SHAREIt app file
→ It's Done. Now just restart your phone and Shareit app will be installed in your phone. Have fun with adnroid.