Here are the instructions for adding drives to a storage pool named “GPStoragePool01” using the Server Manager interface, followed by running the `Optimize-StoragePool` PowerShell command:

### Adding Drives to a Storage Pool using Server Manager

1. Open Server Manager:

1. Press `Windows Key + S` and type “Server Manager” in the search bar.
2. Click on “Server Manager” to open it.

2. Navigate to File and Storage Services:

1. In the left-hand pane, click on “File and Storage Services.”
2. Under “File and Storage Services,” click on “Storage Pools.”

3. Select the Storage Pool:

1. In the “Storage Pools” section, find and select your storage pool named “GPStoragePool01.”

4. Add Physical Disks:

1. Click on “Tasks” next to “Physical Disks” and select “Add Physical Disk.”
2. A new window will appear showing the available physical disks that are not part of any storage pool.
3. Select the disk(s) you want to add to the storage pool.
4. Click “OK” to add the selected disks to the pool.

5. Confirm the Addition:

1. Once the disks are added, the storage pool’s total capacity will increase, reflecting the newly added disk(s).

### Optimizing the Storage Pool using PowerShell

1. Open PowerShell as Administrator:

1. Press `Windows Key + X` and select “Windows PowerShell (Admin)” from the menu.

2. Run the Optimize-StoragePool Command:

1. In the PowerShell window, type the following command and press `Enter`:

```powershell

   Optimize-StoragePool -FriendlyName "GPStoragePool01"
   ```
 - This command will optimize the storage pool, ensuring that the newly added space is properly allocated and ready for use.

### Final Steps:

- After running the `Optimize-StoragePool` command, you should be able to expand existing virtual disks or create new ones using the additional space in the storage pool.

By following these steps, you can efficiently add new drives to your storage pool and ensure that the system optimizes the available space for use.