To invite Warden to your server there's one thing you need:
Manage Server permission or be the owner of the server.
If you have that then you can continue on to inviting the bot by clicking here.
The permissions set for Warden is the ones it needs. Though, it can run without any permissions except send messages, read messages and embed links.
This image below shows how it should look like if Warden can have all the permissions it needs when you invite it.
To setup Warden for your server you can use the settings command.
w!settings <setting name/reset> <value/reset>
When setting a role/channel to either use the mention of the role/channel or the id of role/channel.
This image above is how it looks like if its successful but it may happen that it fails like this example:
Changes wont be made and you have to redo the command with the correct value that is allowed.
Through the dashboard of Warden you can set server settings. Same permissions apply here to set settings.