The Polycom SIP phones support a few different methods for software updates, most commonly utilizing a central FTP provisioning server so that all devices will check a single distribution point for configuration changes and new firmware images.
You can also use 7-Zip or other extraction utilities.
Then double-click the downloaded file to start the installer.
You must be logged in as an administrator on the computer to do this, or follow the prompts to confirm your permission to install.
Also the firmware was packaged differently in the previous SIP versions as the device firmware was provided as two separate binary files, the bootloader image and the application image.
In the 4.x UCS release these were merged into the same binary file.