A real newbie question about setting up a CNAME change.

Does doing the cname change - moving it to unbounce - move my entire site? (I realize that my files and site content still sit with my host)

What I want to do is test specific pages (my signup pages) and have the domain be www.mysite.com/signup. In other words, I want to move my signup pages to Unbounce for testing, but keep the rest of my site where it is.

Is a better solution for someone who only wants to test certain pages and keep their site where it is to set up a subdomain… ie signup.mysite.com?

Any advice is appreciated.