What's important here is to relax and give attention to bodily sensations, but don't try too hard which builds up physical and mental tension. So, relax and pay attention to what it feels like to sit down. If you notice that you've stopped meditating and started to think, gently bring your attention back to the sensation of sitting.
You can sit in the same place every time you meditate or experiment with sitting in different places and on various surfaces. There are no set rules. Try meditating at home, in nature or in your favorite church etc.
Give attention to the bodily sensations for about 5-10 minutes each session and meditate as often as you like. Remember not to try too hard.