Informational
First, update your system. It’s a good practice to follow before installing anything on your system, just to avoid dependency issues and version incompatibility.
You can do this easily in a terminal:
# apt update
# apt upgrade
Then you’ll also need to install curl on your system if not already there:
# apt install curl
Once your system is ready, the installation can be done with only one command, by copying and pasting this into a terminal:
# curl -sSL https://install.pi-hole.net | bash
Follow the prompts....