First of all, it is not possible to add local videos directly, they are introduced through the third party's proxy, Youtube for example.
The simplest way is to click on the video icon, and then insert the video reference code starting with <iframe.
Here is an example of the most commonly way,using YouTube.
Step 1: Click on the "Insert video" button
Step 2: Right-click to view the code
Step 3: Insert the code into the text box and click "Insert Video"
"Done!" Then preview the page to see how it appears
【Source text：by report】
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