If you've never heard of Fibonacci, he was a great Italian mathematician. He observed that there is a natural progression of numbers that is present throughout nature and the universe. Breathing, using that progression to time your breath in and out, can put you at one with nature.
First, a very simple explanation of the Fibonacci sequence. It starts with 0 then goes to 1. You add up the last two numbers, so the next number is 1. Add the last two and you get 2. Add the last two numbers (1 and 2) and it's 3. Add the last two and you get 5, Add 5 and 3 and the next number is 8, then 13, then 21 and on and on. It's really simple
So here is how you can calm yourself into a somewhat happy state. Start by breathing in for 3 counts, hold your breath for 5 counts, breath out for 8 counts. Do this for a couple of minutes, then switch to 5 in, 8 hod, 13 out. Do this for a few minutes until your calm. If you want to try more, go to 8-13-21.
The counting can be at a pace that is comfortable for you. Some people count rapidly, some slowly. Just find a moderate, comfortable pace. What's important is to keep the Fibonacci sequence.