You should hear the metronome clicking away. Each one of those clicks is a beat. A quarter note will occupy 1 of those clicks.
Let’s play a simple quarter note melody using only the white keys. Touch the record button (the red circle located at the top of the screen). After the four click Count-In, choose a white key and hold it down for one click. Then move on to a different white key and hold that for one beat. Continue this process until you reach the end of the 8 measure grid located above the keyboard.
Now, press the play button to hear your brilliant, 8-measure quarter note melody!