Hello
For reference here is the link to the clarification about trials.
The key point is that it is the trail that meets criteria. The markers are anchor points for that trail. The trail should be an official route following a set path and have some sort of unique identifier.
It is often the case that markers are all very similar as it helps identify tat route from another.
So if the markers you are considering are at intersections, those are decision points where you need a marker to ensure you stay on the trail.
Does this help?
Or do you want to provide further details?