This post assumes you've already setup InfluxDB and have Grafana running.
Inserting annotations Annotations are not a special type of resource, instead it's just another metric that you query with a feature in Grafana to display on other metrics. This means the same insert Line Protocol applies to the Annotation.
This post on maxchadwick.xyz greatly helped me get started: Creating Grafana Annotations with InfluxDb Max Chadwick
Per Max's original post it supports html as well, so you could link for example to a build, test result, or anything else you want to link to from your performance statistics.