Roth contributions aren't deductible {regular 401(k) are} so you need to be entered them as elective deferrals (line 7a) in the ROTH 401(K) section.
in the search box type
Keogh
a new window will open
in the jump to box you'll see
Keogh/Sep/Simple.....
double click on it and you can then scroll down where you can enter your ROTH 401(k) contributions
