We speak sloppily about “time management.” You can certainly make decisions based on a time factor. You can choose how to watch time. But the idea that you can manage time is a bit silly. Try telling time “Do this, not that.” Or “Change the consequences of your motion.” Try giving time feedback on what happened.
Maybe I should start a side hustle selling bumper stickers that say, “Time happens.”
What you can (and must) do is manage yourself and other people working with you. You can make choices based on your energy level. You can take actions which shape your energy level. You can direct and redirect your focus. You can give specific directions related to time.