There are two ways to sort activities: Manually moving them with the drag and drop feature or sorting activities via column headers.

To drag and drop activities in your project, click and hold the activity and drag and drop it to your desired position.

You may also sort by any particular column by clicking on the arrow to the right of the column header and choosing your sort option.

You may wish to change your view by selecting the View dropdown and selecting your view option. The column header sorting will then apply to your new view.