Your group services are automatically organized by occurrence date and can’t be reordered.
To reorder your 1-on-1 services, head over to your Services list in your Admin page and drag and drop the 1-on-1 service to the desired position. The order of appearance follows from left to right and top to bottom. Alternatively, you can click on the three dots (⋮) in the upper right corner of the service and use the “Move forward” and “Move back” buttons to change the position of the service.