I have a Cash Charitable amt on 10a that is larger than $300. Line 10b has $300 (the max if you take the std ded). In the review, it says it needs to be fixed. Help

If my cash charitable contributions are larger than $300 do I put the large amount I made in cash charitable contributions on line 10a or does Turbo Tax want me to put $300? It seems I should put what I donated in cash and make sure line 10b has $300. Please advise. I keep getting the error and I need to file my taxes.