Watch the Practice Session 1 online guitar lesson by TrueFire from Learn Guitar 1: First Steps for Beginners (FREE)
Now let's use whole notes and quarter notes with the metronome. Keep a steady pace, and if you get off the beat or get a bit lost, just stop and count until you are back on and then start playing from there. Rhythm isn't easy, so don't get frustrated if it takes you a little while to get yourself in sync with the beat. It will get easier!