Concept of "Companies" and "Contacts"?

Concept of "Companies" and "Contacts"?

We are just getting started with setting up our Zoho Desk. I have Zendesk experience, so maybe some concepts don't translate. Currently I am confused about how to setup my customer Companies and Contacts. (Or perhaps I don't even need or want to?)

I read this article which talks about setting up users specifically so they can access the portal.
https://help.zoho.com/portal/kb/articles/managing-the-customer-portal

However, I'm thinking that regardless of the portal, when a ticket comes in from asmith@somedomain.com, it would be really helpful if the system was able to know "Oh, that email address matches a contact. That is Amanda Smith of North End Kitchen Remodelers." Maybe my thinking is wrong, but without setting up these users in the system, Desk will not know anything about asmith@somedomain.com. Right?

So I have been digging through the setup options looking for ways to add companies and contacts (users) for companies. I also found the article explaining how to import users from CSV, but I continue to think I want to import users into a Customer Company I've created in Desk.

Please educate me! Thanks!