Amending an accepted Federal 2024 return

I e-filed my son's 2024 Federal Return, was accepted, and balance owed deducted from his account.  He then received a K-1 Form.  I am at a loss on how I should go about amending his return using the 1040X.  Where do I enter the K-1 information, or do I submit the form in addition to the 1040X?  I am using TT Deluxe 2024.  Is it possible to complete this task using that software?

 

Thank you for you help