How to install a new design?

Hi, I recently hired a designer to create a new sales page design for this one: <link removed>

I just wanted to know, after he is finished with it, how do I install so that it fits nicely with the current copy?

Is it the same process you go about installing a WordPress theme?

You need to give some more information. It’s not clear what is being created. Is it an HTML layout, a PDF, an image? What do you mean by installing it? Is your site a WordPress site? How do you picture this item fitting onto your page(s)?