The next key you will learn is the "N".  

Looking at your keyboard, notice that the "N" is below the "J"
and slightly to the left.  The "N" is keyed with the "J" finger. 
Without removing the other fingers from their positions on the 
home row keys, reach from "J" down to "N" and back to "J" again. 

Practice this reach until you feel comfortable.

Now, practice this reach as it is called for you.  

Wait for the tone before you strike the key and think each key as
you strike it.

Remember your keyboarding posture!