Forgot to file 1099-r for mega backdoor 401k

Hi everyone! I forgot to file my 1099-R for my after-tax 401k -> Roth 401k conversion (mega backdoor) for my previous year's tax return. Can anyone help me figure out which forms I need to file/steps I need to take? Luckily, I used TurboTax so hopefully, it'll be easy.

 

Thank you so much in advance!