It would help us if you told us what operating system and version you are using.
generic instructions
Windows
1. Right click on the downloaded Camera_Raw_5_7_updater.zip
Click on Extract All
2. In the Extract All dialog check Show extracted files when complete, then click on Extract
3. When the next window opens showing the extracted files, right click on the Setup.exe and click on Run as Administrator.
In the User Account Control dialog click Yes
Just follow the directions in the install dialog when it opens
Mac
1. Double click on the downloaded Camera_Raw_5_updater.dmg to mount the dmg image
2. When the next window opens, double click on the Setup.app
In the next window enter your password
Just follow the instructions in the install dialog that appears
I didn't take screenshots of the installer dialogs, because i already have the 5.7 camera raw plugin installed