NikhilJain
Do you need the distance based on Geolocation (not very accurate) or actual travel distance based on Google Distance Matrix API?
For the 1st one, you can find the function named "getDistance" in the app/Http/Controllers/RestaurantController.php
You will need to pass the origin lat, lng and the destination lat, lng and it will give you the distance between these two location in KM.
Hope this helps.