Location Customization in Wordpress Theme

I have a Wordpress website with Foodbakery theme set up in conjunction with WooCommerce. Here is the theme link: [login to view URL] I will send my actual wordpress website link via chat. The theme is based on restaurant directory, any restaurant can register and user can then order food from them. What I am trying to build is a modified version of the theme for a single restaurant which got multiple outlets in some cities. If you open the above link, you will see 2 text boxes, the first one is of restaurant name which I want to be replaced by a select box which contains the list of cities in India where the outlets of a single restaurant are present. For example - if the outlets of Restaurant A are open in Delhi, Mumbai, Bangalore then the select box should show Delhi, Mumbai and Bangalore. The next box is of user location, now what I want in this field is that user can only select location if it is based in the selected city. If user lives in for example, Jaipur, then typing anything in the location box should return nothing, maybe a message like We're not yet available in your city but if a user select let's say Mumbai then on typing in location box, results should start popping up only from Mumbai. There is also a detect location icon in the location box which should do the same thing - detect location if the user is in one of the available cities and don't detect if not. There is a button next to the location box, I have already set it up to point to the Shop page which is managed by WooCommerce. After location is entered in the location box, if user click on that button, they should be redirected to the shop page with that selected address. It is actually working in my case, if I click on the button with any address, the address is carried forward in the url in GET variable 'location'. Now on the shop page, there are all the products with Add to cart option, if I hover over Add to cart option, the url in the bottom left still contains the location retrieved from the first step. If I click any product, it loads the product page and the location is lost, if I don't click on product and only click Add to cart, the item gets added to the cart and "View Cart" text is shown just below the button but that view cart link doesn't contain the location so it won't be possible to carry forward the location retrieved from the first step to the checkout page. And this is exactly what I want - user selects or detects location in Step 1, selects any item in Step 2 and completes order in Step 3 without having to re enter address. The main focus of the website is on order and delivery, how quickly an order can get through, if the user first wants to go through the menu/shop then it's fine, they can enter location on the last step but the user should also have the option to quickly order any item via setting location, selecting item and ordering it. If you need any clarifications or have any questions, please ask it via chat.