Here are a collection of videos that will give you the basics of using Worbla.
Ge[Bastelt] Worblas Finest Art – German with English subtitles
A great video showing the basic properties of Worbla including heating, shaping, and sanding. Make sure to turn on captions in the video to follow along in English. By the wonderful Cast4art
How to Create Worbla Armor: Coregeek Cosplay & Creations shared this video covering the sandwich method, foam details, rolled edges and shaping items like bracers.
Introductions to Worbla by Mika Nicole, showing basic tools and process, the sandwich method, and tips for finishing your work.
How to Worbla: An Introduction by Aurore Cosplay
Discussing heating, shaping, and joining pieces of Worbla together, showing making small detailed pieces to add to larger armor, and how to sandwich Worbla and fun foam.
Working with Worbla by Jillian Lynn
Another great video discussing the basics, then shows us Jillian working on a shoulder pauldron from League of Legends.