How to send message to phone number?

[kucingcoder]

I have just used this library, there are no tutorials and the documentation is incomplete.
I have made code like this

Consumer<String> QR = ((KodeQR) -> {
    try {
        Map<EncodeHintType, ErrorCorrectionLevel> hashMap = new HashMap<EncodeHintType, ErrorCorrectionLevel>();
        hashMap.put(EncodeHintType.ERROR_CORRECTION,ErrorCorrectionLevel.L);
        createQR(KodeQR, "wa.png", "utf-8", hashMap, 200, 200);
        ImageIcon qrcode = new ImageIcon("wa.png");
        GambarQR.setIcon(qrcode);
    } catch (Exception e) {
        System.out.println(e.getMessage());
    }
});
            
api = Whatsapp.webBuilder()
.lastConnection()
.unregistered(QrHandler.toPlainString(QR))
.addLoggedInListener(() -> {
    JOptionPane.showMessageDialog(this, "Berhasil Login WA");
    this.remove(GambarQR);
    this.revalidate();
    this.repaint();
})
.connect()
.join();

please give me a code example with complete declarations and mention what needs to be imported