Hello Mikael,
- Start grafana: sudo systemctl enable grafana
- Point your browser to your grafana installation, e.g. http://ruuvi.local or http://IP_ADDRESS:3000
- Edit the mac values in grafana dashboards
EDIT: New image runs on http://raspberrypi.local or http://IP_ADDRESS, i.e. on port 80. Therefore there is no need to add :3000 anymore to URL