Hi, I am not too computer savy, but would like to get some instructions on how to set up wifi in my home so I can use my Kindle Fire reader. My internet access is with Time Warner cable using a Motorola SBG 940 wireless router-modem. My computer is connected with it via cable, not wireless. I do have a wireless mouse, though. Somebody told me that I could just purchase a device to plug into my Mororola SBG 940 to obtain wifi for Kindle use. I would greatly appreciate any info or instructions on how to get this setup.

Yes, you merely buy a wireless router that plugs into your router. In most cases it will plug in where your computer now plugs. Your computer will plug into the back of the wireless router.

They sell them everywhere, really Walmart, Target, Best Buy, many discount stores and of course computer stores.
May find some cheaper but I have seen them at 39 dollars and up.

Your SBG 940 is a WiFi router. So your Kindle should recognize it. When you fire up the Kindle there should be a process for detecting wireless networks. Yours should be listed. Just select it.

For more on configuring the SBG 940 see this site:

How to Configure a Motorola SBG 940 to function with the Grandstream - PhonePower Knowledge Base

For specifics on connecting the Kindle to a WiFi hotspot (such as your router) see this:
Amazon.com Help: Wireless on Your Kindle