The time signature tells your child how many beats to put in each measure of a song. If your kid is confused about time signatures, have him clap it out while saying the beat. A 3/4 time signature has three beats per measure, so your son's claps would be 1-2-3, 1-2-3. Likewise, if it's 4/4, it'll have four beats per measure, so clap like this: 1-2-3-4, 1-2-3-4.