Having stocks that are flagged and need review it's because they might have missing information that either wasn't imported properly or aren't easily located within your documents. Some of these missing information could be: Cost basis, proceeds, date acquired, date sold or, description. With a copy of your Form 1099-B you can check one by one to make sure the information that was imported is correct.
If you have more than 25 transactions that need to be reviewed, you might want to enter them as a sales summary instead of fixing them one by one. Below is a link on how to remove those transactions and instead input them as a whole summary
How do I fix multiple “Needs Review” transactions?