Are you meaning that if you play the A major scale, you are unsure where the other patterns fit in?
If this is the case, take your G major scale, first pattern E shape and move it up to A. So that your second finger is playing the an A root, now you're playing the A major scale.
If you move down the neck from there (toward the nut) you would be applying position 5 with that same A root note this time being used with your pinky.
Move up the neck (toward your strumming hand) from our first position on A and you'll be applying the second pattern or D shape.
Basically, the patterns stay in order, if you like. Does this help at all?