Edit the data
In the third tab of the main dialog you have a list of all data sets that you have loaded (from text files).
It is also here you can edit them.
When you press on the button Edit data sets
you'll get following dialog:
Here you can change names of tables and attributes, delete tables, merge two data sets and enable/disable the possibility to analyse a parameter.
To alter which attributes that could be analysed select the data set and press Edit
and the table to the left will be filled with attributes, all attributes that have the check box "ticked" when you press save will be possible to analyse.