Formatting a new partition from the command line is pretty straight forward.
I do it quite often when
playing working with LVM.
So, long story short, format the partition (to ext4 in this example)
Change the "reserved-blocks-percentage" for data partition (optional).
Normally the default is 5%. If it's a file system partition, don't set it to 0 like I'm doing now.
tune2fs -m 0 /dev/sdxy
Check the file system just created
fsck.ext4 -fy /dev/sdxy
and mount it.
mount /dev/sdxy /wherever/I/want
That's all. Remember to add the partition to the fstab file in case you want to mount it at boot.