How do you add subtask in MS project?

To add a subtask in Microsoft Project, first, create a new task that you want to designate as a subtask. Then, select the task and click on the "Indent Task" button in the ribbon (under the "Task" tab) or press the shortcut key "Alt + Shift + Right Arrow." This will make the selected task a subtask of the task immediately above it. You can also create a subtask by dragging the task underneath its parent task and indenting it.