Before adding a new Commercial Order you will need to define Seasons to specify period of time for which the schedule should be added.
Go to Sales > Seasons and click Add new season button. Enter the name of the new season (i.e. Summer 2019, Winter 2019, etc…) and define a period of time (how long should the season last).
Once this is done you can go to the Commercial Orders page, select in the filter a particular Season and click on Add new Commercial Order. In the drop-down list under 'Season' you can find previously added seasons. In the same place you can also add a code for easier internal identification and add one or more clients.