How do I set up the AirPods Find My?

So I lost the left side of my AirPods because I couldn’t figure out how to set up Find My. I’m wondering if it’s possible to set up Find My with only the right AirPod, because I’m scared I’ll lose that one too. Also, is there any way to find the missing left AirPod after setting this up?

In Find My, it says “No location found, AirPods setup incomplete.” I’ve tried setting it up three times using the instructions from this Apple Support page,If you get an alert in the Find My app that your AirPods setup is incomplete – Apple Support (UK) but it still didn’t work.

[Re-Titled by Moderator]