they do so by forming in line abreast, shortest person "falling in" on the farmost right of the company commander.
Determining their initial position in relation to a marker.
This may be a position on the ground or a single person placed previously to the movement.
Often troops determine their spacing on the rank by extending their right arm to touch the left shoulder of the marker, or the person on that marked position, and, then starting from the right, align themselves visually to form a straight row.
The alignment may then be checked by a non-commissioned officer making observations and calling orders from the end of the rank.