Need Help with Step Two Backdoor ROTH IRA Conversion

My reply keeps disappearing. There is no reason for TT or the IRS to believe I have nondeductible contributions as none have been made since my late husband retired in 1997 and he filed his last 8606 in 2015 or 2016 running his “basis down to -0-. I’ve made no contributions since the late 1990s. I have no basis in this IRA or my other self-funded IRA p. I answered “No” to multiple questions including nondeductible contributions, RMDs, and also a question, “Did you inherit this IRA from RBC Capital Markets.” Since I assumed spousal ownership I did not “inherit”.