This chord is a little tougher; you've got to fit all three of your fingers on the second fret, and it can feel a little crowded at first. Start by placing your first finger on the second fret of the fourth string. Next, put your second finger on the second fret on the third string. Lastly, place your third finger on the second fret of the second string. Strum the bottom five strings (being careful to avoid the sixth), and you'll be playing an Amajor chord.
Another common way to play an Amajor chord is by flattening one finger across the second fret of all three strings. This can be tricky, and initially, will be extremely difficult to play cleanly.