This tutorial by user Amos Mibey will show you how to get Telegraf set up on your FreeBSD operating system. Telegraf is an Open Source server agent designed to help monitor data from stacks, sensors, and systems. See the link below for the full set of instructions.

Welcome to our guide on how to install and configure Telegraf on FreeBSD 12. If you are looking at collecting and monitoring FreeBSD 12 system metrics, then you might want to use the powerful TIG stack monitoring and visualization tool. In this case, you can install Telegraf agent for collecting these metrics for analysis.

Full tutorial:

Install and Configure Telegraf on FreeBSD 12