[number + counter] + ずつ 少し / ちょっと + ずつ
ずつ goes straight after a number and counter and means "each" or "at a time": the same amount goes to every person, or comes round every time. Nothing goes between the counter and ずつ.
ずつ needs an amount. It does not go on an ordinary noun, and "each person" with no number is それぞれ.
With すこし少し or ちょっと, ずつ means "little by little": a change that happens gradually, or an amount you take a bit at a time.
A number with ずつ usually comes after the noun and its particle, right before the verb, the way a plain number does. It can also go in front of the noun, joined by の.