This is what I did from the beginning.
if you don't use vim, just replace that with the name of your favorite editor...
$ ip addr # check internet access
$ fdisk /dev/sda
Command (m for help): g # new GPT partition map
Command (m for help): n # new partition (whole disk)
Command (m for help): w # save changes
$ mkfs.ext4 /dev/sda1 # format ext4
$ mount /dev/sda1 /mnt
$ pacstrap /mnt base vim...