The truth is, you have to prepare your body and notice if you have any body issues, before sitting and focusing on the breath.
It is really challenging to sit in stillness as a beginner and even for someone that practices meditation a lot it can be hard to be still because life changes all the time. We all need guidance from time to time. Questions to ask:
How long can I sit today? Can I sit on the floor? Are my hips and hamstrings tight today?
You can it on a chair or the floor or against the wall but it is still important to prepare your body before you sit because, if you’re not comfortable your meditation will always be about the physical discomfort.
Traditionally yoga was a practice to prepare the body to sit in meditation.
If you’re preparing a 5k run and you haven’t run in a year you might want to train a few weeks before the race. That is what coming to stillness is, preparing your body to sit.
Prepare your body to sit, so you can be comfortable when you come to meditation.
Here is a short video from Yoga Journal.