The firmware download includes a PDF that guides you step by step on how to apply the firmware. [URL] Page 8 of the following white paper also has some information on the process. [URL] And here is a video with the instructions. [URL] 
I need to upgrade the ios of the 6248 staked switches , Current ios PC6200v3.3.14.2 . Please advice me how to upgrade stacked switches.  Thank you 
IOS upgrade