The easiest way to brush a baby's teeth is to sit them on your knee with their head resting against your chest.
With an older child, sit or stand behind them and tilt their head upwards cradling their chin in your hand so you can reach their top and bottom teeth more easily. If possible do the brushing in front of a mirror so the child can see what you are doing.

The night time brushing is most important because it helps get rid of all food consumed during the day and also because the cleansing action of saliva is reduced when we sleep so any bacteria left on teeth overnight have plenty of hours to damage the teeth and gums during sleep. Remember nothing to eat or drink except water after brushing the teeth at night.

Brush your child's teeth for about TWO minutes TWICE a day: once just before bedtime and at least one other time during the day. Preferably after breakfast! This I know sounds strange because we've been raised all our lives to brush before eating in the mornings but if you brush your teeth before going to bed at night, then after breakfast is ideal for your next brushing session.