You can delete the event post whenever you want or configure it to delete automatically at a certain time.
If you are not the owner, it is probably a good idea to ask the server's owner permission before doing anything.
Here, you can specify how the bot should work with your Discord server.
Click Setup next to your server name.
Scroll and click the Twitch icon.
Then, click Invite or Add, depending on which site is being used to download the bot.