add the physical
volumes to a volume group
To add physical volumes to a volume group in Proxmox, you can use the Proxmox Web GUI or the command vgextend. 
Using the Proxmox Web GUI 

    Open the Proxmox Web GUI
    Select Datacenter
    Select Storage
    Select Add
    Select LVM
    Select the volume group
    Name the new storage volume 

Using the vgextend command 

    Use the vgextend command to add physical volumes to a volume group
    The command is vgextend [ options ] volume_group physical_volume