How to mount new logical volume (adding to fstab and mtab)?

I created a new LV for the first time using this command:

lvcreate -L 20G -n iew-vm-lv /dev/ubuntu-vg #create the new LV

When I try running mount /dev/ubuntu-vg/iew-vm-lv, I get the following error:

mount: can't find /dev/ubuntu-vg/iew-vm-lv in /etc/fstab or /etc/mtab

How do I add the new LV to those files? Am I supposed to manually edit them?

The current contents of the files are:

# /etc/fstab: static file system information.## Use 'blkid' to print the universally unique identifier for a# device; this may be used with UUID= as a more robust way to name devices# that works even if disks are added and removed. See fstab(5).## <file system> <mount point>   <type>  <options>       <dump>  <pass>/dev/mapper/ubuntu--vg-root--lv /               ext4    errors=remount-ro 0       1# /boot was on /dev/sda1 during installationUUID=93d4132c-7593-4a9d-901e-30d79db3082d /boot           ext2    defaults        0       2/dev/mapper/ubuntu--vg-home--lv /home           ext4    defaults        0       2/dev/mapper/ubuntu--vg-swap--lv none            swap    sw              0       0

And:

/dev/mapper/ubuntu--vg-root--lv / ext4 rw,errors=remount-ro 0 0proc /proc proc rw,noexec,nosuid,nodev 0 0sysfs /sys sysfs rw,noexec,nosuid,nodev 0 0none /sys/fs/cgroup tmpfs rw 0 0none /sys/fs/fuse/connections fusectl rw 0 0none /sys/kernel/debug debugfs rw 0 0none /sys/kernel/security securityfs rw 0 0udev /dev devtmpfs rw,mode=0755 0 0devpts /dev/pts devpts rw,noexec,nosuid,gid=5,mode=0620 0 0tmpfs /run tmpfs rw,noexec,nosuid,size=10%,mode=0755 0 0none /run/lock tmpfs rw,noexec,nosuid,nodev,size=5242880 0 0none /run/shm tmpfs rw,nosuid,nodev 0 0none /run/user tmpfs rw,noexec,nosuid,nodev,size=104857600,mode=0755 0 0none /sys/fs/pstore pstore rw 0 0/dev/sda1 /boot ext2 rw 0 0systemd /sys/fs/cgroup/systemd cgroup rw,noexec,nosuid,nodev,none,name=systemd 0 0/dev/mapper/ubuntu--vg-home--lv /home ext4 rw 0 0