Wow now that's pretty vague about what you have tried.
Here are a series of steps that most likely will work.
1. The BPI-M3 is different than any of the other PI like devices so instructions for other devices will not work.
2. Get one of my images
Burn the image to a SD card the first one is tiny the second 4GB the third is 8GB
i.e. dd if=imagename of=/dev/sdcard bs=1M
remove the card from the PC put it back in the open GPARTED and navigate to the image select each of the partitions and unmount then select each of the partitions and run check then hit apply. You can also resize the image to fill your card at this point.
Insert the sd card into the BPI-M3 and start up.
NOTE the M3 requires much more power than other boards to operate normally see my posts on power and heat sink.
You need at least 4amp at 5.1V feed into the header pins.
Once you reach the desktop open GPARTED on the M3 and format the EMMC on board.
Shutdown and copy the image file to the sd card as an image file.
Reboot to resync everything and use disk to find the correct dev and dd the image file to the EMMC. reboot again
open Gparted and check both partitions then expand to fill the EMMC
Shutdown remove SD and reboot into ubuntu.