Hey there! I'm happy to help!
The Earth rotates counter-clockwise. If you are looking at North and South America, the earth is turning to the right. This means that which ever one is farthest to the right (the East) will have the Sun shine on them first.
As you can see, South America is more to the right, so this means that the Sun will shine light on them first.
I hope that this helps! Have a wonderful day! :D
