Tutorials
Guided paths from "zero" to a working peer connection.
Foundations
WebRTC.org: Getting Started
The official overview: capture media, open a connection, exchange data.
WebRTC for the Curious
A free, open-source book that explains the protocols, not just the APIs.
Hands-On
MDN: Signaling and video calling
A complete walkthrough of a signaling server plus a two-way call.
MDN: A simple RTCDataChannel sample
The smallest possible data-channel example, start to finish.
WebRTC Samples
The canonical collection of runnable, single-purpose demos.