If we need to add a video on our page in magento store lets see how we can do it 

Follow these steps :

1. Login to the admin panel of your setup.

2. In admin panel menu go to CMS menu and click on option page.

3. Then there the grid of all your CMS pages will get open, in our case in that grid search for the about us page. We are add video on our about us page.

4. Click on the about us page and in the left side tabs select the content tab.
Then click on the show/hide editor button to show editor.

5. Now open the www.youtube.com and in youtube search the video you desired to post on about us page.

6. After opening the video click on the share button in the bottom there below that the embedded link will be there copy that link.

as shown in the screen shot below :

7. Then in you admin panel at CMS page about us in content editor paste the link where you want to display the video on the page.

8. Finally click on the save button on right top.

Now, hit the Url of the about us page of you will see the the youtube video on your page at the desired position.