Create a Google Keep note entitled "Arduino Intro". While watching the following videos, take notes. It may help to have two Chrome Windows open side-by-side. If it helps, click this link to open Keep in a new tab, and then drag it away from Chrome to open it in a new window.
After watching these videos, read through this Arduino Tutorial: Learn the Basics page. You won't understand all of it the first time you read it, but it will give you an really good overview of what an Arduino can do!