There are two ways of tracking time in the Daily Tracker.
You can create a category with Time (hours:minutes) values, like in the example below. By doing so, you will be able to manually add/subtract time with the plus/minus buttons.
This is perfect if you are logging time after the fact, for instance when tracking airplane flight hours, swimming time and so forth.
Alternatively, you can create a category with Stopwatch values and use it to measure time intervals. This is ideal if you are interested in precise time tracking.
When you start the stopwatch, it remains running even if you quit the Daily Tracker. As a reminder, you will see application badge with the number of running timers.