Flashing image to microSD results in the root partition running out of disk space

Hi there

I’m trying to flash a linux image to my Odroid XU4 - however upon doing so with Balena Etcher and booting into the OS it reports that there is only 300MB of disk space left on the root partition.

This cannot be since the microSD card is 64GB. Checking around in Linux reports that it can only use around 6.7GB of the microSD. The rest isn’t even visible.

How can I make the flashed Ubuntu installation use the entire microSD size?