Build simple website for employee check in

To build a website that offers the following functions - A back office website (super admin) to set up new admin users. Will need to set up contact information and login details (name, number, address, email and password) - A back office website (admin). The admin will be able to create users (name, contact number, email and password) and will also be able to access map (main screen) - A mobile website (doesn't need to be an app) that supports multiple mobile platforms, that users (will be between 5 and 20 users per admin, so not massive) will log in to. Once logged in they will have the option to turn 'on' and 'off'. If turned 'on' the user will also be able to add a not (up to 200 characters) - If a user turns 'on', their location (via GPS) will display on the admin back office website, on the map on the main screen, (an icon per user) When an icon is clicked, it displays that users contact details, and any notes they have added. - Language and design is to be suggested by developer, should be appealing and professional. No specific design specifications other than this. - I am keen for a quick project time