You need to provide more information so we can help you further. The backdoor IRA is a slightly complicated process that needs careful handling and timing for it to be executed without any issues, like you ending up paying more rather than reducing your taxes.

Details below:

I make more than the individual ROTH IRA limit so I was planning to use this backdoor.

May-2019, I opened a new Traditional IRA Account and Funded $6000 (maximum) using my after tax money.

The very next day, I converted the full $6000 to the ROTH IRA.

Now when I try to enter the details on 1099-R it seems to be adding tax on the $6000 which was already taxed from my payroll. Should I even be declaring this on 1099-R?

Be sure to enter all contributions before the 1099R. Please follow these steps, How do I enter a backdoor Roth IRA conversion?