You can quickly start a new timer in Teamwork Projects no matter which part of your site that you're currently in, by using the Quick Add button in the top right above the search bar:

You can click the 'Start a Timer' option, or to speed things up even more press 'Q' on your keyboard to bring up the menu then press 'S'.

When you choose to start a timer using this menu option, you'll need to pick which project you'd like to log the time on then you can start the timer and it will run in the lower left corner of the screen, and you can log the time to the project when you're ready.