Another way for time tracking is moving cards between lists.
You have to create cards outside of any "DOING" list for example under To Do list,
then when you drag&drop a card on to any "DOING" list then 3T starts calculating time spent on
it for a member that dragged and dropped it, and you will see it as currently in progress there: Overview
When anybody drags and drops it out of any "DOING" list then 3T stops calculating time spent for the user
who dragged and dropped it on to "DOING" list and it will disappear from the Overview page and
will be shown on the Timesheet and under XLS if you set proper Team, Co-Workers, Boards and date range.
You also can specify your own list names in addition to default list names to track time for.