Part 2 of your question
Once you locate your 2024 return in the section Your tax returns & documents, while in that section choose tax year 2024, and click on a link Amend (change) 2024 return
It should then provide the instructions on how to amend the 2024 return.
See this FAQ and video:
FAQ: How do I amend my federal tax return for a prior year?
https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-change-correct-return-a...
Tip: You may wish to save a backup copy of the original 2024 return using a filename that identifies it as the original return.
NOTE: Remember tax return PDFs and data files are very sensitive files containing your personal info and commonly even bank account numbers. So when working with such files, store them safely and securely to protect from ID theft, hacking, etc.
