Meditation & Mindfulness sits in an awkward place online. Search for it and you get either product affiliate links or gatekeeping, with very little in between. This is a quiet attempt at the in-between: a small site about doing meditation & mindfulness at a sensible level, by someone who has been practicing long enough to know which advice survives contact with reality.
The most useful place to start is body scan. Get that right and most of the common beginner problems disappear. sitting posture is the next thing worth your attention. Beyond that, the rest is fine-tuning.