Intro to the Elegoo Super Starter Kit
A good starter kit that includes an Arduino Uno R3 and lots of parts.
Folder of Files from Elegoo
A company specializing in STEM related kits and accessories.
Link to Started Kit Materials.
The kit comes with a CD but can also download the materials.
YouTube Channels
Great tech tutorials including intro video for getting started with Arduinos.
Excellent video to learn about what you can do with Arduino. Very instructional.
The official Arduino Web Site for all things Arduino.