Go to my Account
Go to Company
Go to Apps / Portal
Click Action
Select Iframe Widget

Vimeo

In the IFRAME Widget make sure you paste the following address with the player vimeo reference.
https://player.vimeo.com/video/####### ### is the Vimeo reference.

If you wish to hide this video from Vimeo.

Go to the video setup
Go to General
Go to Privacy and select Hide from Vimeo

Youtube

For Youtube make sure you have the reference as follow:

https://www.youtube.com/embed/#### ### is the Youtube reference.

To show the video on the client portal, make sure you tagged the contact and widget with the same tag.