The easiest way to get to the 1099-R entry screen is to simply search for 1099-R (upper-
or lower-case, with or without the dash) in your TurboTax program and
then click the "Jump to" link in the search results.
Then answer Yes, and click Continue and follow the on-screen instructions to either import or type in your 1099-R form.
If you've already previously entered this form, you'll come to the Your 1099-R Entries screen. Here, you can either edit an existing 1099-R entry, or click Add Another 1099-R to add another one.