I have a project file where some activities were added after the baseline was set.
In fact some of the tasks where further detailed and indented; so as it has now been made a summary task with baseline but the detailed ones does not has a baseline date.
can i copy the baseline dates from the summary task and paste the baseline dates into the detailed tasks?
Your situation is common and can be a challenge to get right. You might want to see if you can find a good blog on the subject, but here’s a short version. Select only those new tasks and any tasks dependent on those tasks, then set baseline for selected tasks and rollup to summaries. It requires a properly managed project (no deleted baselined tasks, etc.). Make sure you validate the rollup to what you would expect (total hours, total costs, etc.).