Hi @PartialBeetle82,
Welcome in the Community !
The platform "Fit Y by X" will automatically display the right type of analysis depending on your variables types, the panel on the left is not interactive (it only displays which analysis will be performed based on your variable types).
If you want to perform a "Oneway" analysis, you need a continuous Y response and a categorical X variable. You can right click in the column title "Level" in your datatable, click on "Column Info", and change the Modeling type to "Nominal" (or Ordinal). Then, relaunching the platform "Fit Y by X", setting your X and Y variables and clicking on "Ok" will directly provide a Oneway analysis.
I hope this answer will help you,
Victor GUILLER
"It is not unusual for a well-designed experiment to analyze itself" (Box, Hunter and Hunter)