How Do I Make My Discord Bot Make A Message Right After It's Launched?

Ok so basically what I'm trying to say is that I watched a few tutorials online on how to make a discord bot (but ya know, I'm not really that good at it) and I was wondering you guys can help me with this SIMPLE problem.

For example: If the bot updates, when the bot comes back online, it outputs a custom message saying its updated. For the most part, I want to understand how to make it so the bot says a message in a channel after I make it come online. Thanks!

BOT SOURCE CODE https://ghostbin.com/paste/q2doq

Use the client onReady handler.

client.on('ready', () => {
  //Or Something else
  var channelToSend = client.channels.get('ID');
  channelToSend.send("test");
});