Park on the A543, only good map reading and an ability to place yourself can tell you where, a footpath leads directly from the road to the stones but it isnt signposted, so ......
Go up the hill untill the ground cover changes from ferns and heather to just grass follow that line untill the path presents itself. Or head for the bridge across the narrow northerly end of Alwen reservoir. The stones are big, on the whole and easily spotted.
As Arthur and me approached the stones a small bird suddenly darted out of the grass, I took a closer look at where it came from and found a tiny little nest full of wide yellow mouths demanding food, as far as cool things to see go it almost overshadowed the stones .
I think there was seven stones, quite large boulders in an oval shape, this is no stone circle, and it was only in adding it as a site that ring cairn was applied as a name, it isnt one of them either. Coflein wont commit to any more than "prehistoric stone setting".
After an exhaustive inspection of the stones and a sit and ponder moment my springwatchian nature took over and I came over all Simon Kingy lieing down on my stomach to have a closer look at the still parentless tiny nest, theres nowt cuter than baby birds, if there is I dont want to know.