Knowledgebase categories

I'm using Zoho's help center as the example for mine. I'm trying to have about 10 categories like Zoho crm help center on my help center home page, but bc the KB is tied to departments it seems,I can only have 2 since I have only two departments on KB. So what am I missing? How was Zoho able to get User guide, admin guide, etc on their home page, with icons and all.