Histogram evolution: visualize how a distribution of values changes
over time (via) has the article
URL slug of 'grafana histogram howto', and the slug is quite accurate.
It's a step by step walkthrough of how to do this for a native
Prometheus counter histogram metric,
which most of them are. It includes copious screenshots, which is
especially useful since you have to do all of this through Grafana's
GUI and describing GUI actions in text is not necessarily ideal.
I've slogged through heatmaps and histograms in Prometheus and
Grafana, and this article
still taught me something quite useful that I hadn't realized (the
'exclude zeros' setting; I agree with the author that this should
be the Grafana default).
PS: Contrary to what the article suggests, heatmap legends aren't
always useful, at least in current versions of Grafana. I tried
putting a legend on some disk IO latency heatmaps that have very
small latencies and the result was not all that readable or clear.