SAMD21 SAM-BA Bootloader via UART

Hello Dude,
I've Arduino M0 board and try to upload sketch file by using UART with SAM-BA bootloader as described in Atmel 42366

The purpose of using UART instead of USB is to upload with bluetooth wirelessly like Arduino UNO Upload Sketch Wirelessly

I've used source code based on mzero with Atmel Studio v6.2.

My problem is that I've no experience on ASF and do not know where to start.

Best regards,
pak