How do I get ZElevation or Zheight?

I was following a tutorial and I followed it but it used ZElevation and ZHeight but when I check there was just Z so when I tested the game with just Z I would just break

Thanks but it is not an offical tutorial but do you think you can help me out? When I change one of the Z's to depth (It was object.z + object.z) it would teleport me up and would make me fall back down. https://www.youtube.com/watch?v=Y1d6Pe5gurE&list=PLivUpw-q07h4oRGetPxYuJ2ma8b4LFbsj&index=2 I dont know how to upload my game but I would like to show you.

When I change one of the Z's to depth

Well, changing a Z co-ordinate for depth is not correct. They are different things. If you previously used the ZElevation expression, use Z instead; if you used TotalZElevation, use TotalZ, and if you used ZHeight, use Depth instead.