After you create an activity, go to Inventory>Packages and add a new package without accommodation:
In the package's settings page, under the configuration section, select duration: Fixed duration - variants and choose the number of days in which this activity will be offered (In this example, we are setting up a surf lesson with a frequency of 3 days).
After adding the variant options, go to the daily configuration section and add the surf lesson activity to both arrival and normal days:
Important: If your package was created using the AUTO pricing option, please make sure you have set a pricing for the individual activity in the Inventory>Activities section.
After completing the steps above, your package without accommodation will be ready to be booked via the frontoffice: