1. How do I close the calladmin

You have to delete the channel itself

2. How can I set it to send to a certain category

Enable discord developer mode > create a category > right click > copy ID > go to the config file > paste the ID into here: "CategoryID": "xxxxxx",

3. Steam Profile Icon, you need to get the Steam64ID of a user profile and enter it here: "SteamProfileIcon": "",

Hope this helps for anyone who has these questions