You'll need a Zapier account and a Twilio account to connect SMS to Slack. Sign up for both if you haven't already, and purchase a SMS enabled Twilio number. Create a new zap in Zapier, selecting Twilio as the trigger app and choosing new SMS from the drop down menu. Connect your Twilio credentials and select the Twilio number purchased earlier. Then, choose Slack as the Action App and post a new message to your desired channel, authenticating with your team's Slack domain and logging in. You can control parameters of the text message, such as the body or user's phone number, before testing the zap with a successful SMS to your Twilio number, allowing you to wire up Twilio numbers to Slack channels for various marketing campaigns or events.