Retirement tax questions

Holy cow that was harder than it seems it should've been.  Thank you.  I guess what confused me was I was looking for a checkbox to say that withdrawl was exempt combined with the reason not being listed specifically when I entered an amount.  

So I entered the amount:

How do I now attach the statement that provides the name, age, TIN of my twins?  I entered them as dependents previously in TT (where all my kids are listed)--is that sufficient to meet this requirement?