The original was a tonne of new yorkstone put down nearly 40 years ago directly on the ground. Needless to say, it sank and we finally decided to have it all up, re-lay it, and enlarge it a bit to take our new reconstitued stone seat.
The ground was more-or-less levelled and hammered down, then covered with heavy-duty weed suppressant fabric, and a layer of chickenwire to act as a bit of reinforcing - there are willow roots under the path which will (I expect) over time cause it to rise, and we wanted to try to make it last for a good while.
The base was Blue Circle Slablayer, poured onto and through the chickenwire, tamped down, watered as per instructions, and then raked and tamped. This gave a reasonable base - but the top surface which was basically sand needed to be removed.
The rest was a question of laying and levelling each stone individually - I got quite good at riving the slabs to make them a bit thinner. We needed more stones, so we got some reclaimed stones which turned out to have black (some sort of paint - not lichen or algae) which we scraped off. Finally, my wife pointed all the joints.
Total - 122 stones (assorted sizes) and about 12m2 of path.
Please feel free to comment and criticise - we're still willing to learn (even at our age)