The Form 4852 is still available for 2018. However, I would recommend the other option:
In TurboTax online program:
1. Sign into your account, select Take me to my return
2. To the right upper corner, in the search box, type in "other reportable income" and Enter
3. Select Jump to other reportable income
4. Next screen, Other Wages Received, select No to continue
5. Next screen, scroll down all the way to the bottom, under Other reportable income, select Start
6. Next screen, Any Other Taxable Income? select Yes to continue to fill the information.
To create a substitute 1099-R, here are the steps:
In your desktop program,
1. To the right upper corner, in the search box, type in "1099r" and Enter
3. Select Jump to 1099-R, follow prompts
4. Select "I'll type it in myself" and continue. See the attached screenshot.