The note C# does not require the use of any fingers. You simply blow through the instrument without covering any of the holes.
This new D note is written on the fourth line of the staff.
To play the high D note, cover all except for the top hole. Keep the first finger of your left hand close to the hole ready to use it for other notes when required.
Now try this melody which uses the two new notes along with all the other notes you know.