not understanding this from everything that ive seen

Ive been reading about haxorware for a couple days but im still slightly confused on a couple things, how i even connect the modem to my pc to flash it, and how to get free comcast internet from it, i had an old sb5101 that was modded to receive free internet, and from all the intel i gathered im assuming it was modded with haxorware, it seems that everywhere i look at other threads, at other sites, everyone says for you to read around, and literally everything that i have read from just says to read around, so i have 3 main questions,
#1. How would you connect an sb5101 to a computer to flash it(video link would be great because i cant find a video)
#2. How would I be able to get free comcast internet with it flashed
#3. If i am right about haxorware being able to mod the modems to get free comcast internet, would i be able to do the same thing with twc or any other isp's

If there is a different forum u have answered these questions on just send me a link of it because ive been looking for days and cant find anything thanks