Hi,
first, you might want to wipe & reinitialize the disk. You can do that by selecting it in the list, then pressing Wipe Disk, afterwards Initialize Disk with GPT. (Make sure you select the right disk!)
Next, to actually use it, you must decide if you want a LVM, LVM-thin or ZFS storage. If this is a consumer NVMe disk and/or don't have any other special requirements (e.g. RAID, replication, etc.), going with LVM-thin for VMs is usually a good choice.
This can by done by choosing the Disks > LVM-Thin in the sidebar and then pressing Create: Thinpool at the top. For e.g. ZFS, a new pool can be created under Disks > ZFS.
Hope this helps!
