First, you need a Twitter account. This is easier than getting a library card, and far less embarrassing when you lose it. Download the Twitter app—it’s the blue bird that looks like it’s seething with rage about something. Log in, or if you’re new, invent a username that isn’t already taken by a bot that posts photos of soup.
Fun fact: over 500 million tweets are sent every day. That’s more tweets than there are people in North America, which means your tweet will be like a single grain of sand on a very loud beach. Don’t let that stop you.