I assume the purchases that you are donating were bought with your own funds rather than you buying the materials on behalf of the church with church funds.
If that is the case you would list the date and amount of each purchase which carries to Sch A along with your other itemized deductions. Keep in mind that your total itemized deductions would have to be greater than the standard deduction of $12,200 if filing single or $24,400 if married filing jointly for tax year 2019.
