using a set node is a one time thing if you want it to loop then you need to add more script to make that happen. for example you could use a timeline and update the set node many times over a given period. or you could set offset on tick which would update the location every frame. then you would need to create some logic if you wanted it to change directions such as comparing the location to a predetermined location or limiting the number of time that the set location can be done before you change the delta to a negative or just running the timeline in reverse once its completed.