How to unschool involves becoming an unschooler. Unfortunately, that's not easy to explain.

The good news is there are several pieces of writing by various people that can help you!

Precisely How to Unschool, by Sandra Dodd, featuring this important scientific measurement:

How to Unschool, by Linda Wyatt

Advice to Remember, by Citimomx3

"How to Be a Good Unschooler" by Pam Sorooshian

Five Steps to Unschoolng by Joyce Fetteroll

How Does Unschooling Work?—Samples and Examples of What Actually Happens

You start by learning about your children. You start by playing with them. By hanging out and listening to them. By starting with them. The more you know about them, the more you know about what interests them, the more you see them and hang out with them, the easier it will be for you to find things that interest them. Don't start by looking at the wider world and trying to force it upon your children. Start with them.

Doing Unschooling Right (with a transcript by Marta Venturini Machado, less than six minutes)
Fazer o "Unschooling" Bem (with transcript and subtitles in Portuguese, and subtitles, by Marta Venturini Machado)