How-To: Setting up a knowledge base in Zendesk Guide

We're looking to set up a knowledge base in Zendesk Guide to help our customers find answers to their questions without having to contact support. We've looked at the documentation, but we're not sure where to start. Can someone please provide a simple, step-by-step guide on how to set up a knowledge base? We're particularly interested in how to create categories and sections, how to write articles, and how to customize the look and feel of the knowledge base. We're also curious to know if it's possible to restrict access to certain articles. Any help would be greatly appreciated!