The Build of Materials is from LCSC. 
If you copy paste their BOM_Supplier Part number into the LCSC search bar, you should be able to find each part.
If you can't find a specific part, almost all SMD components are 0603 and easily findeable from other sources.
The labelled PCB should be used for assembly and the Gerber file is in ZIP format so it can be uploaded to your website of choice right away.
When flashing the firmware, I found arduino over ISP works the best.
Upload the arduinoISP sketch to your arduino uno and then connect the pins as follows

	UNO	C-Duino
Power	5V	VCC
Ground	GND	GND
SCK	13	15
MISO	12	14
MOSI	11	16
Reset	10	RST

Then burn the bootloader to your C-Duino.
For more information, visit https://schou.dk/linux/arduino/isp/
All the pins are the same on the C-Duino and follow the same flashing procedure.