Specifying the data that will be used in your campaign is the most important thing during the campaign configuration. A good definition can easily take you to better predictions.
It is highly recommended a good understanding of the data you will be using in the campaign.
There are three main steps for configuring your data :
naming your columns (and specifying the order).
specifying the type of the columns.
telling nbt which of them are going to be "special columns" (columns with a special and predefined meaning. More later on this).
Naming your columns
The first step is to define the name and order of the columns.
You can do this in two ways :
a) Using a set of the data in a tsv (tab separated values, if you copy and paste from an Excel file to a plain file you'll get a tsv file).
Using this approach you will need to provide the first lines of your data file, and the nbt console will try to get the columns (and types of the columns) from it.
It is recommended you review the data types in a later step.
Just copy and paste in the text area and click on process sample. It can take up to some minutes depending on the length of the data provided.
b) the other approach is doing it manually, inserting the columns one by one. However, it is not recommended using this method as it is more error prone.
Using any of the above methods, you'll end up having a list of columns with a specific order.
Columns can be reordered, or modified in this second screenshot. In fact, its main purpose is to do small modifications on your column definitions (like adding a new column you may think has a good predictive value).
Remember : this definition must match the data that will be provided to nbt when analysing.