Raise whole terrain by an ammount

I made a terrain and realised I can’t lower the terrain to a zero amount. I was wondering if there was a way to raise the whole terrain by a given amount. I noticed this script here

I tried to use it but when I put values in nothing semed to happen. I’m wondering if that script is four an outdated version of unity.

Anyone knows the right way ? =)

Never mind, it’s not a dragable script component as I thought it was, you edit the height under the terrain menu !

for those who still wonder about what kind of script it was or how to use it:

The scripts are called editor scripts, they add features to the terrain tab in unity.

The scripts need to be put in any folder inside your project named “Editor” to work.