For some columns (texts, formulas, link to a table), it is possible to define a default value containing either the user's TimeTonic ID, e.g sam, or the book ID, e.g project.sam.
Thus, when a new line is created, the value of this column will automatically contain the user's or book's ID.
Particularly useful, for example, for new opportunities created by your sales representative in your CRM to be automatically assigned to him, or to identify from which book the new information comes from in your mirror views.
Once the settings window is open, click on the drop-down menu of the default value:
All that is left to do now is to select the default value you want.
Either the User or the book ID: