In the middle step of the send dialog you set when each stage becomes available and a deadline for the whole task. Both are optional: without them the task starts at once and runs until it is done.

A scheduled task reaches the student only at its start time. The notification and the email go out then, not when you press send — a task scheduled for Monday is announced on Monday, and until then the student sees nothing. That is expected, not a failure to deliver.

The Relative switch changes what the stage times mean: instead of calendar dates, each stage opens a set number of minutes after the previous one is finished, so every student moves at their own pace.

At the deadline the task is marked as out of time. A student who never started it can no longer start; a student who is in the middle of it can finish, and everything they have answered is kept. Stages that had not begun are cancelled.

Nobody is notified about a deadline — there is no reminder before it and no message after it. If a date matters, say so in the message you attach to the task.

A deadline cannot be changed once the task is sent. To move it you cancel the assignment and send the task again. Cancelling removes the task from the students it went to.

All times are read and shown in the local time of the device you are using.