Adding YouTube videos is easy with the standard script included:

Step 1: Go to YouTube and find the video you want to embed. In the page url you will see a video id after the v= part. Copy that video id down for the next steps. For example, the video below has a video id of 2O2Li74EYew

Step 2: Add an Inject Anything module to the page

Step 3: In the options, choose the following:

Insertion Point : Module
Source : Standard Script
Standard Scripts: YouTube Video

Step 4: In the Video Id field, enter the video id you got in Step 1

Step 5: Click update and watch your video!