How to make a page into a collection page, without re-doing the work?

Design help CMS
1

Hey, guys,

I’m making my agency website, and after I create the first project page, I realizes that I could use CMS for the projects.
So how can I use the page that I already create to became the project collection page template?

Thank you in advance!

http://manifesto-branding-003.webflow.io/

http://manifesto-branding-003.webflow.io/case1

https://preview.webflow.com/preview/manifesto-branding-003?preview=c8f5404cbd433ee2d2e0cc4ef20df405

2

Create a DIV under the body, drag all the page content into that div, copy the div, paste into collection page template?