Then you must go to Customers > Select the customer > General, press edit and in the "Customer family" section you define the family to which it belongs.
Once you have performed this action, to display all customers belonging to a family, access Customers > Filter > Customer family.
If what you need is to perform the mass assignment of a customer family to certain customers created in STEL Order, follow these steps:
.Go to Settings > Import/Export > Export to file > select type "Customers", then select from available attributes to selected attributes the necessary information to know in the case that it is so what family have assigned each of your customers to be able to update that information, in this way you will get to export a list in Excel format that will give you the necessary information, from there you have to develop an Excel document with the references of the customers and the legal name for each customer family.
This way once you have generated the Excel document with the list of clients assigned to a specific family, you have to go to Settings > Import/export > Update from file, define all the information and in the additional information section choose the family of clients to which you want to assign this generated list, finally select the file, rename each of the columns (ex. reference and legal name) and click on update.