COPPER RIDGE can be installed with nails or cleats.
The nails would typically be 2.5" ring-shank stainless steel gasketed roofing nails, spaced between each pair of underlying slates (approximately 12" apart, but nailed *between* the underlying slates, which will determine spacing).
Alternatively, the ridge can be installed with cleats or straps, which will allow an installation with no exposed fasteners. Use standard or longer-grip copper/brass pop rivets to attach the straps to the ridge.
Here are some photos of cleats on ridges showing other ways to use them: