DON'T Use Auto ISO as a Beginner... Here's Why
When adjusting camera settings, I always recommend that beginners leave their ISO at the camera's base, NOT Auto ISO.
While Auto ISO can be a convenient way to ensure proper exposure of your images in the field, too many pros are using it and recommending beginners to do the same. The issue with this is that the photographer who doesn't fully understand their camera settings will see a properly exposed image on the back of their screen while in auto ISO and not realize that the shutter speed is too fast or the aperture is too far stopped down.
You should ALWAYS use shutter speed and aperture first before utilizing ISO to maintain proper exposure in your image. Otherwise, you risk your images being plagued with noise and low-quality details. As a beginner, it's easy to get in the habit of tweaking the ISO to make the image brighter or darker, but ISO should only be used when you can't get proper exposure with the desired shutter speed and aperture.
For landscape photographers, if nothing is moving in your scene, there is rarely EVER a time where you'll need to use ISO except in total darkness.
So yes, there is always a time and place to use the ISO. But if you're new to manual exposure, learn shutter speed and aperture before you start to crank on the ISO.