Use the M0 connector to connect the PCB to your computer using a programmer.
After downloading the firmware, open
./SmartLight-Firmware/SmartLight-Firmware.ino with the Arduino IDE.
Make sure that your ESP8266-01 is connected to your PC and you choose the right Flash Size with at least 128KB SPIFS for your ESP8266-01.
When you Power On the ESP8266-01 it tries (for 5 minutes) to connect to the saved WiFi Access Point. While doing so he is hosting his own Access Point called "SmartLight - Setup".
Connect to it with your PC or Smartphone and open the URL http://192.168.4.1. The Password is "LightItUp" You must choose your WiFi there and can set up some other things like the type of LED-Strips you connected and what the hostname of the device in your WiFi should be.
After Saving your settings, the ESP8266-01 should restart and the connected light should light up blue. When the ESP8266-01 established a connection to the given WiFi he will turn off all the lights and waits for your commands.