Sending Whatsapp message to a new number.

I’ve been doing this application for a while now, and I cant see to find a way of making it work. I’m using two Text Boxes and a button. My objective is making so in the first box the user can write any number he wants, and being able to write a message to this number in the second box, then sending it, even if he doesn’t have it in their contacts. Thank you, everyone!

Show your blocks and let us know what you’ve tried so far.

You might follow this tutorial.