Help repairing GRUB on LUKS-encrypted volume

[LinuxNewbie]

Hello!

I'm dual-booting using two separate drives; one using Kubuntu 25.10 and another using Windows 10.
However, yesterday when I tried booting to my Kubuntu drive, my PC booted straight into Windows 10 and continues to do so.
Normally, it would boot into the GRUB menu where I can select between the two systems, but not this time.
This leads me to believe that GRUB has been destroyed, since unlocking the drive using a live USB shows an empty GRUB folder in root.
My Kubuntu install has two partitions: sda1 (ext4, kubuntu_boot), sda2 (luks2, root).

I've tried changing the boot order in my BIOS, as well as unplugging the Windows drive, but when I do this, my PC finds no bootable drive.
I believe I need to follow the guide linked here, but there's a few things I don't understand about it:

sudo -i
apt-get update
apt-get install cryptsetup lvm2
fdisk -l
cryptsetup luksOpen /dev/sda? TAG # sda? is your root partition
vgchange -ay
vgscan
vgchange -ay [VOLUME GROUP NAME] # From the above command
lvscan
mount /dev/[VOLUME GROUP NAME]/[LOGICAL VOLUME NAME] /mnt # LOGICAL VOLUME NAME from above command
modprobe efivarfs
mount /dev/sda? /mnt/boot/efi # sda? is your efi partition
mount --bind /dev /mnt/dev
mount --bind /dev/pts /mnt/dev/pts
mount --bind /proc /mnt/proc
mount --bind /sys /mnt/sys
cp /etc/resolv.conf /mnt/etc/
chroot /mnt​

What is [VOLUME GROUP NAME] and [LOGICAL VOLUME NAME], and where can these be found in the terminal?

Thank you!