Thank you for pointing out the change with the Camera ‘Background Type’. This has now been renamed in the newer Unity versions as ‘Clear Flags’ . I will update the tutorial image to reflect this.
On the second issue, check that you have the Package “XR Legacy Input Helpers” added to your project. This should be found in the Project view under “Packages”, otherwise please go to the Window->Package Manager and choose to install the missing package.
When you have the “XR Legacy Input Helpers”, you should be able to choose “Add Component” on the Head GameObject and then add a “Tracked Pose Driver” script to keep going on the tutorial.
Thanks for the comments and I will look to update other the change to the Camera.