I recieved notice my refund was reduced because form 8862 needs to be filled. How do i do this?

See this TurboTax support FAQ for the Form 8862 - https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-forms/enter-form-8862/L0gkFuF6N_US_en_US?uid=lzu2i6oz

To access your current or prior year online tax returns sign onto the TurboTax website with the User ID you used to create the account - https://myturbotax.intuit.com/

When you sign onto your online account and land on the Tax Home web page, scroll down and click on Add a state. 

This will take you back to the 2023 online tax return.