You can use the sorting and filtering options on the Guidance page to find the relevant powers and duties guidance. Sorting the guidance by functions and services allows you to limit the results by service area, which is useful if you're focusing on one department in your organisation. You can also use the checkboxes on the right-hand side to limit guidance by type, the country it's applicable to and the type of authority it's applicable to.
Once you've used the sorting and filtering options, you can download the guidance in CSV or RTF format. It's a simple case of 'what you see is what you get', so play around with the sorting and filtering until you have everything you need.