This is recommended reading in tandem with A Quick & Easy Guide to They/Them Pronouns by Archie Bongiovanni and Tristan Jimerson.
Mady G.'s book is brightly colored, cute and a seriously quick read at 94 pages. It's a guide about queerness and human love and identity as told by some adorable snails who are witnessing a queer education event around a campfire in the woods. The presentation is safe and comforting. 
They/Them, a guide to gender-neutral pronouns, is also a friendly and speedy read at 60 pages. The artwork is more subdued and realistic than Mady G.'s. The two guides complement each other nicely.
Both educational comics are a warm, welcoming place to start. They are short and accessible and intended to help introduce queer and trans terminology and concepts and gender-neutral pronouns. Both books explain what they are, why they matter, how to use them, and give guidance when you make mistakes. Practical information for teens and adults.