How do you know when meditation time is over? There are at least 111 apps out there waiting to help you. Which one is suitable for you depends on how long you want to meditate, how much you will pay (if at all), and whether you want to block telephone calls while you meditate.
We may often be like a leaf being blown from one activity to another. A regular meditation practice may create a chance to take a break from outward activity and create a sense of order and rootedness.