This is the three four time signature.
It tells you there are three beats in each bar.
Three four time is also known as waltz time.
Before you play this song, clap along with the notes, counting 1 2 3, 1 2 3 as you go. Notice that breath marks occur only every four bars here. This is to give you practice at breathing less often. You can still take an extra breath in between the breath marks if you need to.
A dot after a half note means that you hold the note for three beats.
This song contains several dotted half notes. Once again, breath marks occur only every four bars. Notice the whole rest in the final bar. In ^ time, a whole rest means a whole bar rest.