For your new Users: how-to video, guide overlays, or chatbot?

I made a video and it was too large for my site to load efficiently... I've experimented with guide overlays...they're okay, but I don't love how they look. A chatbot could be missed, and doesn't really explain right away to a new User how to use the site... What do you do to help your new Users understand how to use your apps? What's most effective?