我正在使用IntelliJ学习Java，我想知道如何导入我自己创建的类。例如，我有一个名为Projects的主文件夹，在此文件夹中，我还有两个其他文件夹，一个名为Queue，另一个名为List。如何使用Queue.javaList目录中的www.example.com类？我需要以某种方式导入它吗？

public class Queue {
    private Node start;

    public Queue(){
        start = null;
    }

    public boolean isEmpty() {
        return start == null;
    }

    public void enqueue(int element) {
        if (isEmpty()) {
            Node newNode = new Node(element);
            newNode.next = start;
            start = newNode;
        } else {
            Node current = start;
            while (current.next != null) {
                current = current.next;
            }
            current.next = new Node(element);
        }
    }

    public int dequeue() {
        int result = -1;

        if (isEmpty()) {
            System.err.println("Error: The queue is empty");
        } else {
            result = start.data;
            start = start.next;
        }

        return result;
    }

    public void display() {
        if (isEmpty()) {
            System.err.println("Error: The queue is empty");
        } else {
            Node current = start;
            System.out.print("\nQueue ");
            while (current != null) {
                System.out.printf("|%d|", current.data);
                current = current.next;
            }
            System.out.print("\n");
        }
    }