The note C is written in the third space of the staff. Notes written above the middle line of the staff usually have their stems going down.
This song uses the note C along with B, A and G. Take it slowly at first and name each note in your mind as you play. When you can play it easily, try playing it with your eyes closed and picture the fingering for each note as you play it.
This is a whole note.
It lasts for four beats.
There is one whole note in one bar of * time.
A black box hanging under a line is called a whole rest.
It means there are four beats of silence.
Here is another duet. Remember to keep counting regardless or whether a note or a rest appears in the music. Often where one instrument has a rest, another instrument keeps playing.
When your part comes back in after a rest, you will need to be in time with the other part. Counting helps you to do this. Be careful not to confuse the whole rest with the half rest which appears in the final bar.