https://docs.digitalocean.com/products/monitoring/how-to/install-agent/ - provides the instructions to install the DigitalOcean Metrics Agent

This will install a package called do-agent.

If you face any issues during the installation, file a issue at https://github.com/digitalocean/do-agent/issues

One such issue I filed on 2022-12-12 - https://github.com/digitalocean/do-agent/issues/286