One of the quickest and simplest ways to meditate is to sit comfortably (you can do this standing), close your eyes, and count 20 long slow breaths.
There’s really no “wrong” way to do this. If you can maintain enough focus to breathe slowly for 20 breaths, you are doing fine.
Finding time for this and remembering to do it can be difficult, so here's a few tricks:
Right after a shower, before you get out of the shower, stand and do this. For some people, getting out of the shower is a very rushed part of the day, with a feeling of time stress. Since this meditation generally is a bit under 2 minutes (100 seconds if you breathe at 5 seconds per breath, for example), it's not going to eat your day and can help with the rushed feelings.
If your local weather is such, summer or winter, that worming up or cooling down your car is important, this is another good time to practice.
This is not the ideal meditation exercise for trying to fall asleep. I will get into going to sleep meditations in other blogs posts and the next book (as I write this I'm working on a meditation exercise dedicated mini manual)
There are times when you are going to have a huge flood of thoughts coming in while doing this exercise. Let the thoughts go and don't worry about it. While the goal is to have fewer or less distraction from thoughts, realize that just the initial bit of relaxation and mental quietness can allow a logjam of other thoughts to dissolve and run free. As you quiet your automatic self talk, thoughts that you push back or that you are usually distracted from have a chance to be heard. And they "want" to be heard.
So relax and let it flow, maintaining the focus on the breath counts. There's nothing wrong with you!
How to breathe. There's really no need to focus on how you breathe during this exercise. If you want to use a specific exercise, something called Ham Sa breathing is my favorite suggestion.
There are variations on this, and whole mantras and translations. Basically, ham (hawm) is the sound of breathing in, and sa (saaahhhhhh) is the sound of breathing out. The point isn't the sound, though, it's the pushing and allowing. Or, allowing (the inward breath) and pushing (the exhalation). A lot of breathing disorders, including asthma, are due in part to a difficulty in exhalation. With that difficulty there's a lower level of exhalation, which essentially leaves stale air in the lungs.
The hamsa breath, with a focus on allowing inhalation through the nose (if possible, not a big deal if you are stuffed up) and pushing the exhalation out through a half-open mouth, helps to expel stale air and more completely use your lungs.
Generally you want to use your diaphragm and abdominals for the breathing, but you either know about this or don't need to worry about it at first. I'll cover it later, first thing is to get the habit of doing the meditation exercises.
And that's what you need to know. The sounds aren't super important, but they help to remind you to do the breathing (inside or outside of a meditation exercise). There are suggestions for postures of sitting, keeping your tongue on the roof of your mouth, switching nostrils... none of that is really important here, your body will actually figure out the most effective and comfortable way to do it.