Recapitulating what the blueprint is supposed to do:
-as soon as the sphere starts existing, send a pulse through to so everything connected in order (begin play)
-look through the level and fin all instance of the spline bp an put them in an array (for each loop)
-on each thing in this array, set get the spline component that’s inside and set it as a variable (the bit you didnt conect)
-once it has done everything in the loop, play the timeline
-set position of the sphere (by getting a point along the spline that corresponds to your timeline value multiplied by some stuff. This should work if you set your spline variable or if you use the spline from the loop directly, but it is not doing anything right now because the variable is “empty”)