There are two possible fingerings for this note. Learn both of them.
Notes written above the middle line of a staff usually have their stems going down to the left.
This C note is written in the third space of the staff.
As shown in the diagrams, there are two possible fingerings for this note. When using the fingering on the right, make sure you only cover half the hole with your first finger. Play the following example using one fingering and then the other.
Here are some more songs which use the note C natural. Take them slowly at first until you are as confident using C natural as you are with C sharp.
In this duet the melody is played by the tin whistle and the lower harmony part is played by a flute.