If you are unable to click the Generate button during semi-automatic manual generation, even after selecting a video file and entering the video content, it's possible that the selected video is not in an acceptable format.
Please refer to the following for information on acceptable video sizes and file extensions.
▼Can you tell me about the limits and restrictions on images and videos?
https://help.teachme.jp/hc/en-us/articles/900006441863#toc-content-5
Related: Generate manuals semi-automatically from video（Web Browser）
https://teachme.jp/8/manuals/29559304