First, Setup Rcon in a private channel (let's call it #rcon). Choose a specific channel to send messages from (let's call it #d2m). Go to #d2m and write r!d2m add #rcon. RconCraft will send a success! Send a message in #d2m, RconCraft will react with a tick, and it will send the message to the Server. You can download the plugin for a better look of the messages.