Assuming you are starting with an empty disk (whether physical, virtual or presented via iscsi), when you run
You need to make a partition table aka label; this would generally be a GPT one unless you have specific other needs:
Then create the partitions you need. Unless you have specific partitioning requirements, the most common partition set is single partition using all available space:
mkpart primary ext4 0% 100%
Where you would commonly use ext4, but might use btrfs or zfs etc. depending on your need.
will give you all the options available.
To complete the process, just
For more options, while in parted just type