The A natural minor contains exactly the same notes as the C major scale. The difference is that it starts and finishes on an A note instead of a C note. The A note then becomes the key note.
To highlight the difference, the degrees of the scale as they would relate to the A major scale are written under the note names. Notice the flattened 3rd, 6th and 7th.
Here is the full fingering for the A natural minor scale in the open position, moving up to the high A at the 5th fret on the first string. Learn it from memory and then play it with your eyes closed, naming the notes out loud, and then naming the scale degrees out loud.