These fluorescent yellow silhouette markers are used both to establish Line of Sight, but also as movement widgets, to indicate a destination point before reactions are declared. They also look pretty darn cool!
In order to establish Line of Sight, replace the target model with the template, and point the arrow towards the shooter. If the shooter can see the template, they have a shot!
x1 Template A (infantry size: 30mm)
x1 Template B (Large Infantry Size: 40mm)
x1 Template C (Small Dino Size: 30mm)
x1 Template D (Large Dino Size: 40mm)
x1 Template E (Huge Dino/Cavalry Size: 50mm)