said 9 months, 3 weeks ago:
If your class is more of a 101 beginner class, than I wouldn’t spend too much time advertising on social media.
You’ll do better advertising in traditional spaces where “newbies” who don’t know where to start might see your ad.
If it’s more advanced, then social media and a blog, as @kontextb2b suggests, would be a good place to promote it.
And, nothing beats an opt-in email newsletter for getting in front of your target audience, so start building that now if you haven’t already.