Then you have to create special specification attribute for category filter in NOP.
You can name the attribute whatever you like. Just have to map the right attribute later in Category Filter plugin settings.
Here is also important that for multilanguage store attribute name is translated.
This is the name which later is displayed to customer as a filter name.
Then add specification attribute options.
Create an option for each category.
Option name must be exactly the same as category name.
For multilanguage store it is necessary to translate option name for all activated languages.
If you create new category, you also have to create new option to this specification attribute.
NB! Do not use category path as option name. Use only category name as an option name.
For example if product is in category Elektrilised tööriistad >> Akutööriistad, then add two specification attribute options:
Elektrilised tööriistad
Akutööriistad
It is possible to create specification attribute for category filter and add attribute options manually in NOP, but if you import attributes and categories from external source, then it makes sense to create specification attribute and add options to specification attribute during integration.