Sorry, but how does Auggie do the tech work if he cant see the keyboard and what is the green flashlight that he carries in his hand do it....it obviously helps him see but how if he is totally blind

He has special equipment, like the braille display that is hooked up to his computer so that he can read what's on the screen. Same goes for the headphones, he has special software that reads what's on the screen.
The "green flashlight" is supposed to be an experimental project. It's pretty much a cane that uses lasers and can somehow interpret data from what the beams hit.