IRS Form 1099-R does not have columns. It has boxes. Maybe you got something lese in lieu of an actual 1099-R forum? Take a look at what the form looks like at <a rel="nofollow" target="_blank" href="https://www.irs.gov/pub/irs-pdf/f1099r.pdf">https://www.irs.gov/pub/irs-pdf/f1099r.pdf</a> to see.
These are likely three separate Forms 1099-R and you would enter each line as a separate Form 1099-R. Click the Add Another 1099-R button on the Your 1099-R Entries page.
Thank you!