I have some gig work to design a Shopify website HELP!!

So 2 days ago I got an offer to make a skeleton for a Shopify website and they want a skeleton and want the website fully customised.

Now I know how to start this cause I don't know how to make websites on Shopify.

What I am doing right now is using claude code and Shopify CLI and coding the website so I just want to know how to make it and want the best approach to get it done I have 7 days .

Please i really need help here I need to deliver it to the client