Use first PFM version 3.5 here, this will make things more clear.
In filename, officer_filename, standard_bearer_filename you add the file names of the specific unit (without the ".variant_mesh").
In uniform_name, you add the a name of the uniform (you can make it the way you want).
In unit, you add the unit name that you created in units tab in db.
In faction you can even specify the faction that only uses that specific uniform.
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In raw data you don't have to do nothing if you don't create an entire new unit part. To acces db, you can use PFM and/or Assembly kit.