I can’t remember if there’s a chapter in the P7 notes but, if there isn’t, there’s certainly a chapter with a worked example in the P2 notes.
If you work your way through those notes and that example, you should be able yourself to work out audit procedures and potential problems that might face an auditor (how do you tell the age of a cow? How do you confirm milk yields? How can you tell which sheep belong to your client? How do you value the fleeces from the flock of sheep?)