I sincerely hope this helps you to feel more relaxed, try it for 10 minutes or so...and don't worry if it doesn't help! Everyone is different
According to the book, there are four stages to the, I guess, "meditation technique".
1. The first is called "Settling" and is basically, sitting somewhere comfortable. The book suggests sitting on the floor and using cushions, but I just stay sat on my bed with my legs crossed. You can sit on a chair, but hold your posture instead of leaning back on the chair.
2. The second stage is "Bringing Awareness To The Body". It's sort of a body scan, which should only take a minute or two, where you focus your attention on the sensations of touch, pressure and contact that your body is making with the floor or chair. Such as where specifically the sensation is occurring and how it feels.
3. Third is "Focusing On The Sensations Of Breathing". This one means being aware of the change in physical sensations as you breathe in and out. For example, how your abdomen moves as your inhale and exhale, or the sensation of your breath in your nostrils (how it's warm as it exits, and slightly cooler as you inhale).
I don't know if you're familiar with "Box Breathing" from the relaxation techniques in the help section of this site - but the book essentially says to do the same thing: Breath in - hold for a second - breathe out - hold for a second, and repeat. I found that this happened anyway due to the fact that I was paying attention to my breathing and the physical sensation of pressure from my bed underneath me. This stage doesn't require that anything change within you, just simply allow yourself to experience breathing, and basically just focus on it.
4. Now, the final stage is "Working With The Mind When It Wanders". Your mind will wander - it's inevitable. I had only been doing this exercise for a minute before my mind wandered onto why I'd been so wound up to try it in the first place. It's okay for your mind to wander, or for you to start daydreaming or making plans etc., and there's no need to get frustrated over it. When you become aware that your attention has shifted away from your breathing, firstly, congratulate yourself for becoming aware of the attention shift, and perhaps make a mental note of where your mind wandered to, such as "worrying", "thinking", or "daydreaming", and gently shift your attention back to your breathing and the physical sensations of doing so.
"As best you can, bring a quality of kindness to your awareness, perhaps seeing the repeated wanderings of the mind as opportunities to cultivate greater patience, understanding and acceptance within yourself, and some compassion towards your experience".
Try for 10 minutes, or less, or even longer if you find it beneficial.
Good Luck, let me know how it goes!