1. start from creating a controller java class by annotating @restcontroller on class and adding @requestMapping('/api') 2. @postMapping('/conversion') @pathVariable, on controller method 3.calling of service class method (@autowire service class) , writing logic of conversion in service class method and returning the $ Value from service to controller 4. return response entity with value and http success status code 5. via postman or any rest client make a Post call to the API with Uri /api/conversion/{INR value}