Samsung AllShare Cast Dongle "youtube vizio tv" Questions

My vizio SV421XVT is not internet ready ,how do I adapt it You will need to get an external device that will allow the TV to pick up the internet ..... https://www.youtube.com/watch?v=FTd6rnw5IeQ

Vizio wifi and internet ready tv. I've followed all the directions and viewded almost all demos on youtube on how to connect this item but I keep getting the same (Failed to connect via all share cast