Donated new in the box Roman Stone Porcelain Tiles to my local Goodwill Store. How/can I add them to my donations? Thanks.

you have left out a lot of details. so review IRS publication 526 to figure out your deduction. 

https://www.irs.gov/forms-pubs/about-publication-526 

things that could affect the deductibility.

1) how long did you own them

2) your basis and Fair Market Value

3) did you get a written receipt and acknowledgement

4) is the value over $5,000

 

the reporting would be done on form 8283 for non-cash contributions which flows to the gifts to charity section on Schedule A

 

 

As Mike9241 said, you will have to get additional details. but before you do, be sure it is worth it.

 

• This will be an Itemized deduction.  
• The total of all of your Itemized deductions must exceed the Standard deduction before they will take affect.
• You can also see: The difference between standard and itemized deductions, and what they mean

 

The standard deduction amounts for 2024 are:

• $29,200 – Married Filing Jointly or Qualifying Surviving Spouse
• $21,900 – Head of Household
• $14,600 – Single or Married Filing Separately

For 2024, the additional standard deduction amounts for taxpayers who are 65 and older or blind are:

• $1,950 for Single or Head of Household
• $1,550 for married taxpayers or Qualifying Surviving Spouse

After crunching the numbers it the Itemized deduction may not be the best choice for you.

• You can get a value and post the charitable donation.
• You can include this with other Itemized deductions

However, here are some of the limitations to Itemized deductions

• Medical expenses: You can only deduct the amount of your medical and dental expenses that is more than 7.5% of your AGI.
• Mortgage Interest:  You can deduct the interest you paid during the tax year on the first $750,000 of your mortgage debt for your primary home or a second home. If you are married filing separately, the limit drops to $375,000.
• Local Taxes: Your deduction of state and local income tax, general sales, and property taxes is limited to a combined total deduction of $10,000 ($5,000 if married filing separately).
• Business expenses for employees is no longer allowed.
• There may be other limitations that are not listed.
• Finally, the total of all deductions must be greater than the Standard deduction.