Following spline in VR

Hi, I am at a point, where I am at a loss, because nothing I try works.
I am a noob, just trying to learn.
So my project is in VR, I use the VR Template. I want the player to move along a spline when using a (any at this point) button. That’s it. But i am so confused about everything. I tried to follow this tutorial, but the template has so much stuff already in the event begin play, that it breaks when trying to fit this in there. Also followed Camera/Player follows spline in 1st Person - #11 by Mosel3y, but it confuses me. Any help is greatly appreciated.

In the end the player should move by the controller going up and down (it will be mounted to a rocking chair), but thats in the future. I would be already very happy, if the motion worked.

Hi. What parts are breaking after your changes?
You posted at the international/German board, so if you like we can switch to German.