New hard disk issues with the DS220+

Hello, everyone. So I have a 4TB hard drive in a single volume storage pool. I upgraded the NAS with an 8TB hard drive. I added it to the storage pool, it spent the entire night initializing it, and it now appears in the storage pool’s Drive Info list. The issue is that the volume has remained unchanged. I can’t create a new volume because of the Raid type, and I can’t find a button to add the drive to the volume. Is there something I’m missing? Thank you for your assistance.