It is important that your students rotate to all four centers each day. It can be a patterned clap, a bell, a song, or a specific word. During the first week of school, have your students walk through the centers to understand the procedure. This will allow students to rotate in a clockwise or counterclockwise fashion. Practice this several times to show your students how you expect them to do this.
Parents can be of great help with centers.
Set up a volunteer calendar at the beginning of the year to schedule different parents to come to class and run one center. Have a schedule on each center's board that shows who is running the center and a general title for the center. After all of the parent volunteers have arrived for the day, explain each center to the children and the volunteer. If possible, have directions and sample work at the centers for parents to refer to. One center should always be guided reading with the teacher.