For children, jalan.net uses the following categories, which can be access by clicking on the link "0名" :
小学生 means children going to school - I guess 5 years old and older;
幼児 is for younger children, and then you have the choice between the following plans :
食事・布団あり - with meals and a futon
食事あり - with meals
布団あり - with a futon
食事・布団なし - without meal nor a futon
In your case, you should select "1" in the last box.