sudo apt install software-properties-common
wget -q -O - https://packages.grafana.com/gpg.key | sudo apt-key add -
sudo add-apt-repository "deb https://packages.grafana.com/oss/deb stable main"
sudo apt update
sudo apt-cache policy grafana
sudo apt install grafana
sudo grafana-cli plugins install grafana-piechart-panel
sudo systemctl start grafana-server
sudo systemctl enable grafana-server
sudo systemctl status grafana-server
As an end result you should be able to reach your Grafana endpoint by calling it in a browser window: http://IP:3000
By default port 3000 is used. The default user is admin and the initial password is also admin, which is strongly recommended to be changed to a much stronger password.
Also make sure that your firewall allows you to connect to your Grafana endpoint.
In Grafana first add Prometheus as a new data source under Configuration. Define "Prometheus" as name for the data source and as URL enter "http://localhost:9091" if you are running all components (Grafana and Prometheus on the same instance). Otherwise you will have to enter the IP of the machine where Prometheus is running instead of localhost - "http://IP:9091".