The double bar line at the end of the song tells us that the song is finished.
Do not worry if you cannot play one hole at a time yet. Simply make certain that you are aiming your lips at the correct hole and breathing correctly.
When you are better at finding the correct hole, you can play using single notes or chords. You will find that it sounds fine either way.
The two dots at the end of this song are called a repeat sign. This means that you play the song again from the start.