Watch the Slide the Guide online guitar lesson by Brad Carlton from Chord Studies: Beginner Chords Vol. 1
In this pair of chords, where we change from the E chord to the A, you'll be introduced to a new principle called a "guide finger". A "guide finger" stays on the same string as you change from one chord to another, but changes frets. Guide rhymes with slide, so simply slide your first finger up from the first to the second fret when you change from the E to the A. Also, always check the diagrams to make sure you are sounding only the correct strings in each chord.