Any brand new HDD is completely empty. That means that Windows (or any other OS) cannot access it at all. There is a process YOU must do to get it ready for Windows to use. (Since you can "see" it in Disk Management, obviously you have Windows installed and running.)
Go into Disk Management where you can see the HDD. RIGHT-click on it and choose from the mini-menu to Create a New Simple Volume on it. In one process, this will do two important tasks for you - Create a Partition, and Format it. Some notes to help.
1. There are two types or Partition systems now in wide use. The older one, called MBR, can deal with any HDD up to about 2.1 TB, so if your HDD is not more than 2 TB, you can use this. The newer type is called GPT, and it can handle any HDD to a HUGE size not even made yet. You CAN use if for drives under 2 TB with no trouble; you MUST use this style if your HDD is over 2 TB. Either way, the Partition created will be known by Windows henceforth as a "drive" with its own letter name like F:.
2. The Partition you create does NOT need to be bootable since you already are using an SSD to boot into Windows from. Unless you have plans to add a bootable second OS on the HDD, it can be non-bootable and just not used for any OS. You will find an option for this choice.
3. Most people would choose to make the new Partition take up all of the space available now on the HDD. But if you plan to make two or more separate Partitions to use as different "drives", you can make this one less than full size, then come back and create a second (or more) Partition from the remaining space.
4. Formatting is the process that installs all the files on the new "Drive" necessary for Windows to use the space and track all its files. By far the most common system for this, and one you should use unless you have special requirements, is the NTFS system.
5. You may find an option for doing a Full format or a Quick Format. A Quick Format is pretty fast and creates all the necessary file structures, but does no testing of the drive. By default the normal system will do a Full Format in which it does that file creation task, then goes through the entire drive and tests it. If it finds any weak spots it will take note of them and mark them off never to be used, so this is a good measure to prevent future trouble, However, it can take hours to do this job, so just be patient.
When the process is complete, I suggest you back out of Disk Management and reboot. You will find the new drive fully accessible in Windows now.