What kind of design shall i use in this scenario?

I am new to designing softwares, and I am trying to build a Tree like struct.
I have an empty interface like this:

interface Node{
}

Two classes NodeA and NodeB implement this interface, and both have some specific attributes. Except that these are Nodes, they dont have anything common in them.

class A implements Node {
    public String a;
    public A(String a){
       this.a = a;
    }
}

class B implements Node {
    public int a = 5;
    public String z = "xyz";

    public B(int a,String z){
         this.a = a;
         this.z = z;
    }
}

I have a a class Parse that creates instances of the above classes , depending on certain conditions.

class Parse {
    List<Boolean> l;
    private static int i=0;
    Parse(List<Boolean> l){
        this.l = l;
    }

    private Node parseA() {
        return new A(/* param */); // Assume some parameters here
    }

    private Node parseB() {
        return new B(/* param */); // Assume some parameters here
    }

    private boolean getNextState(){
        return l.get(i++);
    }

    public Node parse(){
        boolean x = getNextState();
        if(x){
            return parseA();
        }
        else{
            return parseB();
        }
    }
}

Driver class:

public class Test {
    public static void main(String[] args) {
        List<Boolean> l = Arrays.asList(true,false); // so on...
        Parse p = new Parse(l);
        Node b = p.parse();  // not sure if its NodeA or NodeB
    }
}

After building the tree, i am planning to use visitor pattern to retrieve some attributes and do some operations.

So at last, when i get a Node b, i want to access its attributes (of NodeA or NodeB), which i know cant be done as Polymorphism doesnt work that way.

I think that using instanceof ladder and type-casting arent proper solutions to it.
Sorry for this silly problem, but being new to designing, i aint getting what to do next.

How shall one solve this design problem? can anyone share a small design structure for this, assuming that this structure will grow bigger and have ample of different nodes. [may be Java Generics help here]

Note: chaning above design is fine,but if possible, a small sample code is appreciated.