+There are numerous YouTube videos on meditation. This one is short and relaxing to listen to. If you search YT using the keywords “meditation” and “cancer” you will find other meditation videos that may be more to your liking. Sitting postures will vary, but the important thing is to sit quietly and to allow relaxation to overwhelm you.
I started meditating on and off back in the 1960s and then got serious about it in 2006 when I became a guest in a Benedictine Oblate group in Washington State. In Oregon I meditated with a Zen Buddhist group AS a Benedictine Oblate. Now as a cancer survivor I meditate daily in my room 20 minutes in the morning and 20 minutes in the evening. I sit quietly on a Zen meditation bench without any background music. While doing this I ignore* the traffic sounds, loud TVs, kids playing, and other noises where I live.
If you are fortunate to find a meditation group in your area that is accepting new members, check it out.
*Some people find noise intrusions, even just the ticking of a clock, keeping them from meditating. It may take some time to get used to letting noise intrusions just pass through the mind. Let the dark clouds clear and the sun shine in!