This is the correct post to read for how to set that up Discord Notification Webhooks for Worlds/Colors
basically Create a webhook on the channel you want to get the exo announcements setup on (right click properties, create webhook)
Optionally get the user group you want to @ by typing @groupname then adding a \ infront it and hitting enter and you should get something like <@&12345>… 12345 is the group number you need.
then read that post, send a pm and you are done.
if you want sovereign announcements then repeat the “create webhook” step on a 2nd channel, if not then dont request those, its specifically an additional step.