flagstones for zone 0 house perimeter — thoughts/tips?

I’m looking into putting a 5’ flagstone perimeter around our house to help with fire resistance — not required in my part of Berkeley but seems prudent! I’d like to do the work myself. A natural/rustic look is great; I’d actually prefer if it didn’t look super manicured. Any tips/best practices/cautionary tales? All appreciated. Thank you!