>>25259See with a channel moderator (direct message) after joining and being welcome by the bot giving you the instructions if unsure but since you only really have to manually send the archive, [Creator] Content, timestamp (content warning maybe) should do.
If everything is okay your uploads will be forwarded to the private sharing channel. If you're still confused just send a direct message to the moderator here (Usah 'Sojamee) and they'll help you.