Calm Breathing Tools

There are many breathing Techniques/Tools that are used to help calm minds, ease anxiety, create focus, etc. 

Breathing exercises can help you relax, because they make your body feel like it does when you are already relaxed. Deep breathing is one of the best ways to lower stress in the body. This is because when you breathe deeply, it sends a message to your brain to calm down and relax.

(uofmhealth.org)

A basic tool is slow breaths. Just in and out. In through the nose, out the mouth. Sticking to it til you can maintain a steady, even rhythm. 

Square Breathing is like a square. Breathe in through the nose to the count of 4. Hold  to the count of 4. Release out the mouth to the count of 4 then pause to the count of 4. Again. The square. 

Deep, even opening the lungs. Working to the solar plexis and diaphram. Relaxing. You can start with a lower count of 3 and work up to a 4.

Another technique (webmd)

How to Do Alternate-Nostril Breathing

1. Sit quietly somewhere you don't need to give any tasks your full attention.
2. Bring your right hand up to your nose and move your forefinger and middle finger out of the way. ...
3. With this nostril covered, close your eyes and exhale fully and slowly through your left nostril.

Another used by many is 

Belly breathing

• Sit or lie flat in a comfortable position.
• Put one hand on your belly just below your ribs and the other hand on your chest.
• Take a deep breath in through your nose, and let your belly push your hand out. ...
• Breathe out through pursed lips as if you were whistling. ...
• Do this breathing 3 to 10 times.

Another being

Breath Focus (webmd)

While you do deep breathing, use a picture in your mind and a word or phrase to help you feel more relaxed.

1. Close your eyes if they're open.
2. Take a few big, deep breaths.
3. Breathe in. As you do that, imagine that the air is filled with a sense of peace and calm. Try to feel it throughout your body.
4. Breathe out. While you're doing it, imagine that the air leaves with your stress and tension.
5. Now use a word or phrase with your breath. As you breathe in, say in your mind, "I breathe in peace and calm."
6. As you breathe out, say in your mind, "I breathe out stress and tension."
7. Continue for 10 to 20 minutes.