Retirement tax questions

My wife left the ministry we both worked out and is rolling over her Employee Retirement account into her Roth. We are planning on recording half of it for this year and the other half next year. on the screen its asking me about 2017, 18, 19 & 20 distributions. 2020 does say (before 2017 tax return due date) So should I put the remaining amount we plan to rollover for next year in the 2020 box or not?