Seems you partitioned your disk in a different program, not fdisk
.
If this is an empty disk, then better to start over
sudo fdisk /dev/sda
Then d
and Enter
and repeat until it say Partition 1 has been deleted.
Then n
and Enter
, p
and Enter
, then hit Enter
until got a prompt
Command (m for help):
Now q
and Enter
.
Create a fs:
sudo mkfs.ext4 /dev/sda
I fixed the guide to use a whole disk.