Ride Leader Questions On Messaging

I volunteered to be an alternate ride leader today for a group ride (scary).  I’ve never done this before but I am tech savvy being an engineer.  Can someone tell me how to effectively use Discord and what others are calling unified remote to put messages on the screen for everyone to see?  I’ve never used Discord yet and have no clue how the unified remote app works with Discord and Zwift.  I have only used Zwift’s Mobile Link app for texting.  Help!