To set the order in which your services and categories should display in your online booking tools, you can drag-and-drop them in your services management page. Just head to Setup > Manage services and follow these steps:
Flip the drag-and-drop slider to change it to green
Click and hold the three lines on the left of the service or category name
Drag the service or category and drop it where you want it to be positioned.
When you're finished, be sure to flip the drag-and-drop slider to change it back to pink.
Using this tool, you can also drag services between categories.