How can I install a collectd to promethes exporter plugin?

since I don't want to rely to InfluxDB and Prometheus but only to one, I'm trying to install some exporters that are not available as opkg packages but I have no idea on how can I do it.

For example I want to install this plugin: or I've found this inside the OpenWRT packages but I think I have to manually add it in some ways?

There's a tutorial or something similar?