Hi Ian,
Firstly welcome to the Forum.
Smudge has already posted some excellent links / info above that may well cover your initial question - & there are certainly lots of good / useful videos on this topic around.
Also depending on exactly what you have in mind, as there's certainly a lot of different options out there, from ready made runs of walls, to detail / paint, to making up a basic shell former to then add details / stones too, to complete build your own stone by stone kits - if you fancy a full life sentence perhaps.
There are also quite a few examples of dry stone walling builds on various threads on the Forum here to, but often within layout threads, so perhaps not so easy to find; but might be worth another search too.
Let us know how you get on whatever, Cheers for now, Norm