C# dotnet and mobile app developer

i need a mobile application (cross platform) by preference XAMARIN , to track drivers route and time , these information will be sent through an api that will communicate to the existing website's backend , the website is developed in c# dot net technologies , the website main rol is to take reservation which is then converged into the backend , now we need to add a new tab in the backend to attribute these transport transfer reservation to specific drivers and then the driver will get the planing in the mobile app which will then be acepted in the app itself and then the app will track the driver locations and time in each specific check points and then can complete his task and mission. other development will be done on the website back office also .