Reordering
Press and hold a task for a moment, then drag it to where you want it.
If your list is grouped into sections (for example Morning, Afternoon, Evening), you can drag a task into another section. It takes on that section, so dragging into "Evening" makes it an evening task.
Some sections have their own sort order, and you can't drag within those.
Screenshot to add: Dragging a task in My Day
Bulk editing
To change many tasks at once:
Tap ⋮ at the top right.
Under Actions, tap Bulk Edit.
Tap the tasks you want to select, or use Select open, Select all or Deselect all.
Use the pills and buttons in the drawer to change them all: schedule, list, labels, duration, complete, duplicate, delete, snooze, backburner and more.
Deleting asks you to confirm first.
Screenshot to add: Bulk Edit with several tasks selected
Setting a repeat only works on one task at a time.