You can extract the RAR file with WinRar (Windows) or The Unarchiver (Mac)

You will get a UFS file that you can put in the following default locations: 
 
Macintosh HD/Library/Application Support/UVISoundBanks (on Mac) 
C:\Program Files\UVISoundBanks (on Windows)
 

After that your soundbank will appear in UVI Workstation's Soundbanks list.