For the beginner, there seems to be an infinite amount of courses out there, but why not pick one from people that both have a PhD in clinical psychology, have decades of experience with meditation and one of them have even trained as a Buddhist monk in Thailand, Burma and India.
Get it at:
https://soundstrue.lpages.co/mindfulness-daily/
As far as I know, this course used to be 60 USD and I am not sure if it keeps being free. I haven't tried it yet, myself but having meditated for close to 10 years, I will still be looking forward to trying it.
Maybe we could even start a Steem meditation group if there is any interest?