How to define a node class for multiple tree nodes that have 4 values assigned to it?

Since you're new to Java the most basic structure would be like this:

public class Node {
    private Node parent, left, right;
    private Integer data;

    public Node(Node parent, Node left, Node right, Integer data) {
        this.parent = parent;
        this.left = left;
        this.right = right;
        this.data = data;
    }

    public Node getParent() { return this.parent; }
    public Node getLeft() { return this.left; }
    public Node getRight() { return this.right; }
    public Integer getData() { return this.data; }

    public void setParent(Node parent) { this.parent = parent; }
    public void setLeft(Node left) { this.left = left; }
    public void setRight(Node right) { this.right = right; }
    public void setData(Integer data) { this.data = data; }
}

If you want to take it one step further and learn more about Object-Oriented Programming I would look into generics.

public class Node<T extends Comparable<T>> {
    private Node parent, left, right;
    private T data;

    // Getters, setters, compare methods here
}

This will let you declare a Node<Integer>, Node<String>, Node<CustomClass> to let you not be restricted to a certain type of data. You'll want to do extend Comparable<T> so that you can easily compare objects when doing an insert(), and other Tree functions.