How can I see when I stopped or started a timer?
By default, your timers will only show you the duration they've run, not the time they were started or stopped.
If you want that information, your account can be set to show timers according to start and end times instead of duration. Any Administrator can make that change from Settings > Edit Preferences. In the Timer Mode field, choose Track time via start and end time, then save your changes. This is an account-wide setting and will affect everyone who uses the account.
Note: the Week View of your timesheets will be disabled when the Timer Mode is set to Track time via start and end time. Your team will only be able to track time from the Day View of their timesheets.