Retirement tax questions

"To use Form 4852 to prepare a substitute Form 1099-R, you go through the Form 1099-R section itself.  Choose to type in the information for the Form 1099-R instead of trying to import it.  Then, check the box showing you need to prepare a substitute Form 1099-R and follow the instructions on the screen. "

 

At what point does this option appear? "Then, check the box" --- when does that show up? I'm using Turbo Premiere online. We have a set of1042-S forms (erroneously sent in place of a 1099-R, but that's a separate painful story). So I have to improvise filling out the 1099-R because the fields do not match.  When does the option to "prepare a substitute 1099-R" appear? (This option should make itself known in advance.)