WANTAGH - Children returned to class today in 62 Long Island school districts. A longtime Wantagh principal has suggestions for parents whose kids are going to school for the first time."Just tell them to have a great day and to be as calm as they can be and listen to directions," Forest Lake School Principal Maureen Goldberg says.Schools in another 51 districts open their doors tomorrow. Babylon, Oysterponds, Levittown and Tuckahoe welcome kids back to class Thursday.