This is what I do.
I stack two cushions on my zabuton, though the floor works fine too if your knees can take it. (My legs are long so I need two cushions to raise my backside off the ground. You may need one or three – find what works for you.)
I sit on the cushions in what is called the Burmese Position. Sometimes I sit half-lotus, sometimes I sit full-lotus, sometimes I sit upright in a chair. I swing my body to the left and right to find a good center of balance. I turn my head and stretch my neck. I set my timer to thirty minutes and begin.
I take a deep, slow breath. I feel it brush against my nose. I feel my diaphragm fill. I feel my mind calm a bit. I let it out slowly. I feel it brush against my nose. I feel my diaphragm contract. My mind calms further.
If my mind is being particularly troublesome, as yours will likely be when you begin, I count my breaths. I repeat the previous paragraph’s instructions, and at the end of each exhalation think to myself “one” then “two” then “three” until I reach “ten”. Ten breaths. When my mind is being troublesome I often don’t make it past three before I forget that I am breathing and become distracted by work to be done, memories I enjoy, memories I don’t. When that happens I say to myself, “Ok. Let’s try this again.” And I begin again at “one”.
If my mind is being cooperative, I just breath. I don’t count my breaths, I just watch them. And after awhile, if my mind is being very cooperative, I don’t even watch them. I just breathe. When thoughts arise, as they always do, I try not to follow them or let them disturb my breathing.
Sometimes I like to imagine an endless ocean, where my thoughts are the waves at the top. But as my thoughts slow down, I begin to sink deeper into dark, cool water. This deep, cool water is always there, but you can’t see it if you’re hanging out on the surface.
Your mind is going to hate this exercise when you start. Your mind is used to being in control, of seeking out stimulation. By meditating you are asking your mind to do something it is not used to doing. It is like asking your lungs and your legs to come along with you when you begin running to get healthy. They will protest at first, but eventually, with practice, they will come around.
Beyond this is to get into specifics, which I do not want to do. A simple Google search will introduce you to many different forms of meditation. What I want to impress on you is that they are all good. Pick one you like and work with it. Don’t worry if you’re doing it wrong. You are a beginner and a beginner will necessarily do things wrong. That’s no reason not to begin.