Uploading Media

Is there an example on how to upload media using the startUpload method?
I tried to upload a media using this guide https://developers.google.cn/my-business/content/upload-photos?hl=vi , but I didn't succeed.
Also, is it possible to upload a video at all? I tried using source Url but I got 'Video uploaded from post is not currently supported.'.

Thanks,
Martina