For the ears, here you go:
The top of the ear generally starts in the where the eye is. This varies with each person but generally I would say in the middle of the eye is a good guideline. It ends in the space between the upper lip and the bottom of the nose.
The bottom of the ear connects to the jawline.
If you were to draw a straight line from the centre point at the top of the head and dropped it straight down to the bottom of the neck, the ear would be right in the middle of the line. (This is assuming that the head is standing straight and neck is not slouched etc)
Hope this helps
EDIT: Also, the eye rule is hard to understand, but hopefully this will make it easier.
I tend to go by this pic.
Here you go
Notice that the “5 eye” rule includes the distance between the side of the head and the edge of the ear, bear that in mind.
I would also make sure you are editing your model in orthographic mode and utilizing the front and side view modes. It makes things like proportions easier to follow.
I think you would also benefit from adding in some background images to Blender to work from while modelling if you haven’t done so already.
And finally, do remember that these things are just guidelines. Not every human face is the same and I think it’s kind of cute that Anna does look a bit like an alien. I would try not to make her super proportionally perfect, to keep some character to her.