Once you have defined some activities for your new project, you can start registering time on them. To start the time registration, you first select the activity you will work on in the main window. Then you press the "Start working" button (or double-click the activity or simultaneously press the "Ctrl" and "Space" keys). Time registration has now started!
Once you finish your work, you click on the "Stop working" button (or simultaneously press the "Ctrl", "Shift" and "Space" keys); you don't need to select the activity first, since TimeTraces already knows on which activity you were working.
If you are already working on an activity and you want to start working on another activity, you do not need to press the "Stop working" button first. Simply select another activity, press the "Start working" button, and time registration will automatically be stopped on the previous activity and started again on the selected activity.