State tax filing

I worked in DE in 2020 and didn't acknowledge box 16 as DE withholdings. I report box 16 withholding as my NJ tax withheld. Now I have to amend my return to claim the credit provided for tax received by DE to reduce a balance owed with the state of NJ. No problem there.

Im looking for assistance on how to file with the state of DE to reclaim those monies paid. Is that the process or do I simply take my credits on my NJ return for monies withheld by the stae of DE?