There are a variety of different ways to meditate. So, you might want to do some googling to see what style suits you best.
Get an egg timer and set it for ~10 minutes, then I’d say the best way to start is to sit somewhere quiet in a comfortable position but with good posture, so your back is straight, shoulders down, hands somewhere (folded in your lap would probably work), head bent slightly forward, and your eyes should be nearly closed, but not quite entirely closed. You want to be comfortable but you don’t want to be doing anything that screams, “go to sleep” to your body.
Then pick a unit of time (pick something comfortable, somewhere between three and five seconds). Inhale through your nose for that unit of time, counting. Then exhale through your mouth for twice the unit of time. It should be easy and free. If you feel yourself quivering near the end of the exhale, shorten the period of time. Do that until the egg timer dings.
The once you’ve got the breathing down, which will take a while, stop thinking. It sounds easy, but it really isn’t. Just try to clear your mind. You’ll find that there is all sort of chatter going on in there, that you never really notice. In Buddhism, they stress impermanence, so if something happens to float into your mind that is OK, but you can’t fixate on it. You’ll find yourself getting caught in little loops, where your mind will try and latch onto things. Don’t let it. The counting is helpful to keep a clear mind.
Here is the wikihow, it does a pretty good job of explaining it.
It takes a while for it to work, so keep at it. At first, nothing will happen and it will be, frankly, boring. Keep in mind that there are plenty of peer-reviewed articles that have shown the benefits of meditation to be real. It isn’t some hokey thing with circumstantial evidence backing it up, though it is done by a lot of hokey people. Keep at it for maybe three weeks and then take inventory. If you like it, keep doing it and consider going at it for longer periods. If you don’t like it, well, then leave it be.