Someday/Maybe

MS Planner use the Someday column/bucket (10th from the left) to determine the Someday/Maybe tasks. S/M tasks will remain in the Someday/Maybe view until you remove them.

Hard Dates

In MS Planner, Due Date is the hard date: To assign a hard date: Click task. Click the Due anytime field (pop-up). Select a date (calendar, pop-up)