There are many types of meditation. This simple meditation on the breath will get you started.
When you first meditate it can be helpful to set an alarm for 15 minutes unless you are happy to drift off to sleep at the end of your meditation. (If you are sleep deprived you probably will fall asleep while meditating in the early stages of learning to meditate.)
Find a quiet place where you won't be distracted or disturbed. Sit or lie comfortably. If you choose to sit, keep your spine straight but your shoulders relaxed.
Once you are comfortable, close your eyes and breathe slowly, feeling the air enter your lungs. Next, exhale slowly, feeling the air leave your body through your nostrils. Keep the focus on your breathing. If your mind wanders off, gently bring your focus back to your breathing. You want your attention to remain on your breathing to keep you in the present moment. This way you won't be distracted by past or future events that may carry your mind away and possibly bring anxiety.
Practice this for 15 minutes each day.
It can be especially helpful right before bed if you notice your mind is racing.