Haven't you read the Release announcement for Release 28 on the website? There it is explained clearly:
May I ask you why you haven't asked this question in the corresponding thread? It doesn't fit here.
Would it be possible that you copy the title into your post and change the title to sth. like 'Change default formation'? Then it may be found better by other searchers...
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See also the corresponding FAQ chapter: How can I get units to move as individuals and not in formation?
For unit ranks i think you could have something like
Basic: No shirt, pants or loincloth. Plain shield
Advanced: Simple tunic without pants
Elite:Simple tunic with or without pants, cloak, painted shields.
Champions: Torcs, finer tunics with pants, finer cloaks, painted shields. Perhaps headdress or some kind of leather/cloth armor for champions too.