Q Light Controller+

I have mention system and am trying to make it work. The procedure that made it quasi working was:

#1 Disable Blutooth (add row in /boot/config.txt: dtoverlay=pi3-disable-bt)
#2 Enable UART (add row in /boot/config.txt: enable_uart=1)
#3 setup GPIO 18 as output and set it high (i made python script and have to start it after every boot:

import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BCM)
GPIO.setup(18,GPIO.OUT)
GPIO.output(18,GPIO.HIGH)
)

the problem is that i want to make this automatic at startup. Does anyone have idea where is qlc configured to autostart so i can start my script before it_

Thanks.

P.S. For #3 I had to reinstall RPIWiring

sudo apt-get purge wiringpi
sudo apt-get install wiringpi

QLC+ starts via a SYSV script: