Trying to get a block to move up and down but it keeps only moving up

I am a total newb but I really want to figure this out. My timeline has the Z value go from 0 to 3, then back to zero. This results in the cube I am placing to continue to advance slowly upwards in starts and stops. I want it to return to its original position and go back and forth. Here is my blueprint:

and here is my timeline:

Your graph is always returning a positive value, so it will always go up. Try moving the points on the timeline to be half below and half above the 0 line

Thanks, Grogger. That worked. I have a question, though. Is that the most efficient or accepted way to do something like that (getting a block to move up and down)?

It depends on what you’re trying to do, but for moving something up and down, I might tend toward using the built in physics (add a force to counter gravity - lock movement to the z axis so it doesn’t go sideways if that makes sense for you), that way the physics engine is aware of all movements on it’s terms, rather than having to adapt to what we say.

Note, I haven’t experienced any difficulties setting locations manually though.