Every disk partition is simply an empty space with a beginning and an end.
Unless the partition is being used for swap space, you have to put some type of file system on the partition before it can become useful. Normally, the file system is a native Linux file system, which at this time is called ext2 . The Linux version of mkfs has been nicely streamlined and requires hardly any input. You can continue to execute mkfs commands to create file systems for every partition on your new disk. Your disk has been physically added to your system and partitioned, and you've added file systems to it.