How to Add a Style Guide to an Existing Webflow Project

Hey ya'll. I accidentally made a webflow project without copying the style guide first, designed it, bought a basic plan for it, and attache dmy custom domain. I recreated the site with the style guide in a new webflow project, but don't want to pay again for a basic plan and have to reconnect my custom domain. Is there any way to add the style guide to an existing project or not really? I tried copying and pasting from the second project but it's still not working properly. If it's possible, could anyone share the steps?