How to make another section your index.html instead of the Home button

Hi there,

I am creating my first e-commerce site. It is a mini site connecting to a current live site where you can just Shop. I have had to make the site look and feel identical to the original as the client doesn’t want the user to know that they have gone onto another site. The current site is built with Weebly and I am building the Shop on WP. My question is this:
How can I make the Shop button connect to the index.html instead of the Home button. The Home button will go back to the clients current site. Bearing in mind that I have not used the menu tabs in the backend to set up the navigation, but have copied and pasted the navigation from the original site into my style.css and header.php.
It looks like my shop categories I can still use Woocommerce setup in the backend. It is just this one Shop page. I can’t even view the metaslider that I downloaded for the homepage (Shop page) either.
Do I need to creat a layout on index.php or a custom page?

Any advice would really be much appreciated.
Thanks very much
Colleen