what is the first step that shows an error in the solution to the equation

The correct way to do this is,
DO THE FIRST EQUATION FIRST SO THAT YOU DONT GET OVER WHELMED.
STEP1: 3x+4-4=3x -2-4= -6
STEP2: 3x-6
Now, divide both sides by 3.
STEP3: 3x/3 -6/3
STEP4: x=-2
SO your answer will be x=-2.