Using todoyu's time tracking feature, you can record the time spent on each task. To start the timing session, click on the desired task and press the start button in the time tracking section. Use the stop button to end the session.
All time tracked on a day will show as time sheet in the top-level tab PORTAL. Also you can check the time tracking journal for working hours on past days and months by clicking on the Show Time Sheets button. Select the month in the pull-down menu of the journal and choose Show Details to see not only days but also tasks by day.