Where/How do I enter a Return of Principal reported on a 1099-B?

I received a Composite Statement of 1099 Forms from Raymond James & Associates.  In the 1099-B section of the statement it reported the redemption of the Guggenheim US 50 unit investment trust that I purchased in 2018 and held to maturity in 2019.  Dividends were paid monthly and reinvested in the trust.  There were 12 Short Term Transactions for Noncovered Lots and 2 Long Term Transactions for Noncovered Lots that I entered manually in TurboTax.

 

There was one  Nondetermined Term Transaction for Noncovered Lots that was identified as a Return of Principal.  Where or how is this entered in TurboTax?  Is a Return of Principal the same as a Return of Capital?

 

If it is a Return of Capital, do I need to go back and adjust the cost basis of all transactions that occurred prior to 03/072019?  Or, can I simply adjust the cost basis of my original purchase of the trust?