No worries, I said I'd help you and I'm glad to do it. I'll watch the videos, which one does show the effect you want?
I don't understand what you mean here:
I understand only pin number 4, it is not possible to turn on the direction. Only with pin 6, and pin 4 switches to the other direction indicator. This must work independently that pin 6 can be used to turn the right turn signal on and off. By contrast, the pin 4 must also work independently to turn the left turn signal on and off. In this code, it is not possible to turn on the left blinker with pin 4. You must turn on the right turn signal with pin 6 and then hold the mass on pin 4 then the left direction works.
Pin 4 should be connected to a switch. This device provides either LOW or HIGH to pin 4, depending on the direction it points to. Did you read how to connect the switch in the URL I recommended? So depending on the value the pin receives, the left turn or the right turn signal is shown. At least, this is what I tried to code 
Then, pin 6 is connected to the so-called mass signal. For now, it launches the wave and another push stops it.