1. Go to http://console.developers.google.com
Sign Up if you don't already have an account.
2. Create a new project or use an existing one.
3. Enable YouTube Data API v3 by clicking on "Enable API's and Services" and search for "YouTube".
4. Click on Create Credentials > API Key
6. (If you are asked) What data will you be accessing, select "public data".
7. Click on "What credentials do I need?" button.
8. Copy/Paste your API key to Content Gorilla and click authorize.
You're now ready to start using Content Gorilla.