How And Where To Enter A Roth IRA Conversion in the Plan

I can't find where to tell the program I will have a Roth IRA conversion. Where is this done?

You must have an investment set up with an 'Account Type' of Roth IRA. You can then add the conversion information in the 'Annual Contribution' section as you see in the screenshots below. In this example this person is converting a manually entered dollar amount by year. 

Note that the program will add an inflation adjustment to these entries. For example, if it is 2024 and you enter a $10,000 amount to convert in 2031 and your inflation assumption is 3%, the future dollar amount of that conversion for that year will be $10,000 * (1+3%)^7 = $12,299.