To add a video from YouTube to your webpage:
1. Open youtube.com and upload your video or search for existing one.
2. Open video and click the "Share" button.
3. Choose "Embed" and copy selected code.
4. Open "Text" block editor of your webpage.
5. Click on "html" and you'll see a box expand.
6. Paste the code and click "Update".
7. Click Save.