Deductions & credits

Four questions:

I donated our piano to a 501(c)3, for which we have an unsigned online appraisal of $1,500 and receipt from the non-profit.

1. How do I enter this into Its Deductible, which limits me to $500?

2. Should I send a copy of the appraisal after e-filing?

3. Can I safely include additional item donations of up to $5,000 in each of the following 3 categories: clothing, furniture and books? 

4. I mistakenly entered the wrong year (2020, when it should be 2021) for a list of item donations.  How do I edit the date to move them from 2020 to 2021 without having to reenter all the items?

Thank you for your assistance.