Use a .htm doc without embedding

Site URL: https://containerville.co.uk

Hi, 

I have a virtual tour that has been built as a .htm page with various folders for skin, fonts, media etc. (see screenshot of folder)

This is currently hosted on another domain so it doesn't look like its part of our website. https://s3-eu-west-1.amazonaws.com/skyedge.co.uk/tours/Containerville/v040/index.htm

Its quite a heavy piece of code so i don't want to embed the code (especially as there are subfolders of content that are required for it to work)

How can I go about using these files on my Squarespace site without having to embed code / upload files? Is there a way to upload to FTP and simply create a subdomain for this?

Thanks for your help!