Retirement tax questions

My return for this year used the standard deduction as I did not have enough deductions to file long form so I did not have a schedule A for my federal return.  Just a simple return 1040-SR with no attached schedules.   The issue is that I had a Charitable contribution of $300 that was correctly noted on line 10b and line 10c.  10c is the total of 10a and 10b.  However, I did not have any adjustments to my income from schedule 1, line 22.  However, the $300 also showed up on Social Security Benefits Worksheet on line 6.  I cannot find anywhere in my search that a cash charitable contribution would qualify as an adjustment to income that would be recorded on Schedule 1 (Form 1040).  I would assume the IRS would be looking for this form to be attached to my return noting the adjustment to income.   I think the issue is how line 10 of the 1040-SR is structured.   Both 10a and 10b are adjustments to income; however, I  think they are a stand alone line adjustments to income since line 10b entry is a Charitable contribution adjustment to income and 10a entry is the total adjustments to income from Schedule 1.   I would really like to hear from someone from TT on this issue that would support their calculations.  As I am new to this forum, I do not know how to post this issue in the "Lounge" as I have not heard of it.