Tradition tells us, and private revelation confirms, that the first person to ever walk along the path of the passion, retracing each step, and reflecting on each moment, was our Blessed Mother. It is said that many times Mary visited the scenes of the passion and oftentimes invited close acquaintances and St. John or other apostles and disciples, when they were in town, to accompany her. Presumably, those who did it with her proliferated the practice and continued sharing it with others after the Assumption.
In 313 each stop on the pathway was officially marked. Pilgrims would travel from all over to walk this pathway, retracing the steps and reflecting on the moments just as the Blessed Mother did. The devotion continued to grow in popularity and in the fifth century, an interest developed in "recreating" this pathway in other areas for those who couldn’t actually travel to the holy land.
In the 1700's, 14 stations were made the official stations and it was asked that all churches include markers of what had now become known as the Sorrowful Way, or the Way of the Cross.
The Church sees this commemorative practice as so important and valuable in our faith lives that it has declared a plenary indulgence to be granted for those who piously exercise the Way of the Cross, actually moving from station to station where they are legitimately erected and while mediating on the Passion and death of our Lord.
The station reflections come from Catholic Online. Here is their PDF if you'd like to follow along:
Here is our pray-along version of the Stations of the Cross: