How do I add a page to muy website with the same template and header?

I want to add a button that will take me to a blog within my domain. Example: http://www.HNlegaloffice.com is my main website, but will like to publish my posts to http://www.HNlegaloffice.com/publicaciones. When I do that, my new page http://www.HNlegaloffice.com/publicaciones has the default looking "Spirit" Theme. I would like the new page to conserve all the customizations I have done to my webste in the past days. I would like the same colors, same logo and infor in the header and the same menu. I would only like whatever is underneath the slide show to be changed by by blog posts.

I hope I have explained myself correctly.

Sincerely,

Alejandro Herryman
alejandro@herryman.com
787.667.2210