How do I put text fields and buttons under each other?

Question

package numerical.project;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.JLabel;
import javax.swing.JButton;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class NumericalProject {

    public static void main(String[] args) {
        JFrame frame= new JFrame("Numerical");

        frame.setSize(400,100);
        FlowLayout flow= new FlowLayout();
        frame.setLayout(flow);
        JLabel L1= new JLabel("Equation"); //label
        JTextField T1= new JTextField(10); //textfield1
        JLabel L2= new JLabel("A Value"); //label2
        JTextField T2= new JTextField(5); //textfield2
        T2.setEditable(false);
        JLabel L3= new JLabel("B Value");
        JTextField T3= new JTextField(5);
        T3.setEditable(false);

        JButton b1= new JButton("Calculate");
        frame.add(L1);

        frame.add(T1);
         frame.add(b1);
        frame.add(L2);
        frame.add(T2);

        frame.add(T3);
        frame.add(L3);

        frame.setVisible(true);
    }
}

How do I put text fields and buttons under each other?

For example, I want to put the label equation next to it the first text field, the label A value next to it the 2nd text field, B value next to it the 3rd text field, and at the center the button.