How to add new tasks and add them to the baseline without updating baseline information for the previous tasks which are already tracked?
To set a Baseline for selected tasks, first select the tasks (using the Shift or Ctrl keys) then go to Project – Set Baseline. In the Set Baseline dialog select “Selected tasks” and click the “OK” button. This way the Baseline for the selected tasks will be set. The Baseline will be set when you Save your project.