Website upgarde

I would like to upgrade my existing website by adding new features such as adding a top menu bar with logo and replacing the current menu bar and having an instant pop up cart on the side with the ability for the customer to add a note to the order (please see attached images of what i want the new website feature to look like) i would also like to implement a three step feature to my site that i can add underneath all products and the homepage to push bundler purchasing and make it easy for the customer to do so and potentially even drag and drop products, i have shown a rough idea of what this could look like on a diffrent website but i would need the features changing slightly and the ability to push our three step process (please see final picture).

my current website is : www.prankpackages.co.uk and the images show a changes i have made in a diffrent shopify theme i would like implemented to the current website, and the three step process design and code i need designing from scratch and implementing to my current website if possible.