So just like my other guide, this is more for my own records so I can come back and refer to it.

I know there are scripts for these things, but I prefer doing them manually so I can learn along the way.

Maybe it can help someone else in the future.

Obtain the VM image

- Navigate to the installation page on the HA website: https://www.home-assistant.io/installation/alternative

- Simply right-click the KVM/Proxmox link and copy the address

- In your Proxmox console, use wget to download the file

- Expand the compressed image

unxz </path/to/file.qcow2.xz>

Create the VM

General:
- Select your VM name and ID
- Select 'start at boot'

OS:
- Select 'Do not use any media'

System:
- Change 'machine' to 'q35'
- Change BIOS to OVMF (UEFI)
- Select the EFI storage (typically local-lvm)
- Uncheck 'Pre-Enroll keys'

Disks:
- Delete the SCSI drive and any other disks

CPU:
- Set minimum 2 cores

Memory:
- Set minimum 4096 MB

Network:
- Leave default unless you have special requirements (static, VLAN, etc)

Confirm and finish. Do not start the VM yet.

Add the image to the VM

- In your node's console, use the following command to import the image from the host to the VM

qm importdisk <VM ID> </path/to/file.qcow2> <EFI location>

For example,

qm importdisk 205 /home/user/haos_ova-12.0.qcow2 local-lvm

- Close the node's console and select your HA VM

- Go to the 'Hardware' tab

- Select the 'Unused Disk' and click the 'Edit' button

- Check the 'Discard' box if you're using an SSD then click 'Add'

- Select the 'Options' tab

- Select 'Boot Order' and hit 'Edit'

- Check the newly created drive (likely scsi0) and uncheck everything else

Finish Up

- Start the VM

- Check the shell of the VM. If it booted up correctly, you should be greeted with the link to access the Web UI.

- Navigate to <VM IP>:8123

Done. Everything should be up and running now.