Open your Google Slides presentation
Select the slide where you want the video to appear
Click Insert
Choose one of the following options:
Select Video
Choose Google Drive to upload or select a video from Drive
Choose By URL to paste a YouTube or other supported video link
Choose From YouTube to search and select a video
Click Select to insert the video
Resize or reposition the video as needed
(Optional) Click the video and choose Format options to adjust playback settings
(Optional) Click the video and select Auto play or Start at click (if available)
(Optional) Click the video and set Trim options (if available)