Animate Cube with Timeline

Hey,

New to blueprints/scripting in general

I am trying to create a platform that moves up/down using the timeline.
I am only able to get it to move up at the moment.
Was curious what I am missing to get it to loop up and down instead of just up.

Also I would like to make this a class blueprint. I know I have to use World Transform instead of actor, I am just unsure what else I need to do.

Thanks.