How do I place a child backlog item separately from its parent epic in the backlog?

To place a child backlog item separately from its parent epic in the backlog, hold down Shift while dragging the child backlog item to another place in the backlog. You can also open the popup dialog for the backlog item, and select another backlog list in the "Backlog list" field.

For a backlog item that doesn't already belong to an epic, you can add the backlog item to an epic while keeping its current location in the backlog by right-clicking and selecting "Add to epic". For example, this is useful if an epic represents a high-level goal or theme, and you want to add a backlog item to that epic without changing its current location in the backlog.

To place a child backlog item inside its parent epic, drag the backlog item into the parent epic, or right-click and select "Place inside parent epic".