Here's a sample Positional Data definition file that you can reference to build your own Positional layout according to your data.
The attached sample Definition File follows this pattern:
Field Name, Description, Type, Date Format, Time Format, Start, End, Length, Align, Skip
FirstName, ,String, , , , , 20 , L , F
You can skip the Description, Date, Time, Start, End fields and keep them empty and fill the main columns such as Field Name, Type, Length, Align and Skip. In order to build this definition file, you can use an excel file to create this definition format and save it as a csv file and upload it as shown in the below screenshot.
Using the Default Layout Builder, you can select the following properties:
Select Field Length in the Field Separator field.
Select Import Definition File in the Definition Mode Field
Select Field in the Definition File field
And upload your definition file and it will automatically generate the layout and show all the fields in the Layout panel as shown below.
Also refer to Documentation: https://docs.adeptia.com/display/AC40/Positional+Layout
Attached sample definition file.