How to clone Memberstack into an existing Webflow page instead of creating a new site?

Is this Video outdated?,
He clicks on Clode in Webflow and it says "paste in Webflow". It does not do that for me.
When I press "Clone in Webflow" it wants me to create a new Webflow Website every time and does not let me Ctrl V it into my existing page? I need help asap 

Please